Fix invalid HTML comments

The line "---" indicated to the pre-DocC build system's code testing
infrastructure that the code listing contains a blank line at that
point.  However, two hyphens in a row is invalid inside of an HTML
<!-- --> style comment.

Changed to blank lines because that was another way to spell the same
thing in the old test system (although it might have been fragile, and
was less used), but more importantly we're unlikely to use the old test
system again.  These test expectation lines were preserved during the
export to assist writing new expectation markup in some future testing
system.

Bulk edit via:

    sed -i'' -e 's/^ *--- *$//' TSPL.docc/*/*.md

Confirmed no change to the Render JSON from DocC.

Author: amartini51

TSPL.docc/GuidedTour/GuidedTour.md

@@ -255,7 +255,7 @@ occupations["Jayne"] = "Public Relations"
   ```swifttest
   -> var fruits = ["strawberries", "limes", "tangerines"]
   -> fruits[1] = "grapes"
-  ---
+
   -> var occupations = [
          "Malcolm": "Captain",
          "Kaylee": "Mechanic",
@@ -317,7 +317,7 @@ let emptyDictionary: [String: Float] = [:]
   ```swifttest
   -> let emptyArray: [String] = []
   -> let emptyDictionary: [String: Float] = [:]
-  ---
+
   -> let anotherEmptyArray = [String]()
   -> let emptyDictionary = [String: Float]()
   ```
@@ -432,7 +432,7 @@ if let name = optionalName {
   -> var optionalString: String? = "Hello"
   -> print(optionalString == nil)
   <- false
-  ---
+
   -> var optionalName: String? = "John Appleseed"
   -> var greeting = "Hello!"
   -> if let name = optionalName {
@@ -658,7 +658,7 @@ print(m)
      }
   -> print(n)
   <- 128
-  ---
+
   -> var m = 2
   -> repeat {
          m *= 2
@@ -1132,11 +1132,11 @@ class NamedShape {
   -> class NamedShape {
          var numberOfSides: Int = 0
          var name: String
-  ---
+
          init(name: String) {
             self.name = name
          }
-  ---
+
          func simpleDescription() -> String {
             return "A shape with \(numberOfSides) sides."
          }
@@ -1202,17 +1202,17 @@ test.simpleDescription()
   ```swifttest
   -> class Square: NamedShape {
          var sideLength: Double
-  ---
+
          init(sideLength: Double, name: String) {
              self.sideLength = sideLength
              super.init(name: name)
              numberOfSides = 4
          }
-  ---
+
          func area() -> Double {
              return sideLength * sideLength
          }
-  ---
+
          override func simpleDescription() -> String {
              return "A square with sides of length \(sideLength)."
          }
@@ -1276,13 +1276,13 @@ print(triangle.sideLength)
   ```swifttest
   -> class EquilateralTriangle: NamedShape {
          var sideLength: Double = 0.0
-  ---
+
          init(sideLength: Double, name: String) {
              self.sideLength = sideLength
              super.init(name: name)
              numberOfSides = 3
          }
-  ---
+
          var perimeter: Double {
              get {
                   return 3.0 * sideLength
@@ -1291,7 +1291,7 @@ print(triangle.sideLength)
                  sideLength = newValue / 3.0
              }
          }
-  ---
+
          override func simpleDescription() -> String {
              return "An equilateral triangle with sides of length \(sideLength)."
          }
@@ -1471,7 +1471,7 @@ let aceRawValue = ace.rawValue
          case ace = 1
          case two, three, four, five, six, seven, eight, nine, ten
          case jack, queen, king
-  ---
+
          func simpleDescription() -> String {
              switch self {
                  case .ace:
@@ -1562,7 +1562,7 @@ let heartsDescription = hearts.simpleDescription()
   ```swifttest
   -> enum Suit {
          case spades, hearts, diamonds, clubs
-  ---
+
          func simpleDescription() -> String {
              switch self {
                  case .spades:
@@ -1679,10 +1679,10 @@ case let .failure(message):
          case result(String, String)
          case failure(String)
      }
-  ---
+
   -> let success = ServerResponse.result("6:00 am", "8:09 pm")
   -> let failure = ServerResponse.failure("Out of cheese.")
-  ---
+
   -> switch success {
          case let .result(sunrise, sunset):
              print("Sunrise is at \(sunrise) and sunset is at \(sunset).")
@@ -1982,7 +1982,7 @@ let bDescription = b.simpleDescription
   -> let aDescription = a.simpleDescription
   >> print(aDescription)
   << A very simple class.  Now 100% adjusted.
-  ---
+
   -> struct SimpleStructure: ExampleProtocol {
           var simpleDescription: String = "A simple structure"
           mutating func adjust() {
@@ -2309,13 +2309,13 @@ print(fridgeIsOpen)
   ```swifttest
   -> var fridgeIsOpen = false
   -> let fridgeContent = ["milk", "eggs", "leftovers"]
-  ---
+
   -> func fridgeContains(_ food: String) -> Bool {
          fridgeIsOpen = true
          defer {
              fridgeIsOpen = false
          }
-  ---
+
          let result = fridgeContent.contains(food)
          return result
      }

TSPL.docc/LanguageGuide/AccessControl.md

@@ -195,7 +195,7 @@ private func somePrivateFunction() {}
   -> internal class SomeInternalClass {}
   -> fileprivate class SomeFilePrivateClass {}
   -> private class SomePrivateClass {}
-  ---
+
   -> open var someOpenVariable = 0
   -> public var somePublicVariable = 0
   -> internal let someInternalConstant = 0
@@ -284,18 +284,18 @@ private class SomePrivateClass {                 // explicitly private class
         fileprivate func someFilePrivateMethod() {}  // explicitly file-private class member
         private func somePrivateMethod() {}          // explicitly private class member
      }
-  ---
+
   -> class SomeInternalClass {                       // implicitly internal class
         var someInternalProperty = 0                 // implicitly internal class member
         fileprivate func someFilePrivateMethod() {}  // explicitly file-private class member
         private func somePrivateMethod() {}          // explicitly private class member
      }
-  ---
+
   -> fileprivate class SomeFilePrivateClass {        // explicitly file-private class
         func someFilePrivateMethod() {}              // implicitly file-private class member
         private func somePrivateMethod() {}          // explicitly private class member
      }
-  ---
+
   -> private class SomePrivateClass {                // explicitly private class
         func somePrivateMethod() {}                  // implicitly private class member
      }
@@ -557,7 +557,7 @@ you must explicitly declare the nested type as public.
   -> let publicNestedInsidePublic = PublicStruct.PublicEnumInsidePublicStruct.a
   -> let internalNestedInsidePublic = PublicStruct.InternalEnumInsidePublicStruct.a
   -> let automaticNestedInsidePublic = PublicStruct.AutomaticEnumInsidePublicStruct.a
-  ---
+
   -> let internalNestedInsideInternal = InternalStruct.InternalEnumInsideInternalStruct.a
   -> let automaticNestedInsideInternal = InternalStruct.AutomaticEnumInsideInternalStruct.a
   ```
@@ -569,12 +569,12 @@ you must explicitly declare the nested type as public.
   ```swifttest
   // these are all expected to fail, because they're private to the other file
   -> let privateNestedInsidePublic = PublicStruct.PrivateEnumInsidePublicStruct.a
-  ---
+
   -> let privateNestedInsideInternal = InternalStruct.PrivateEnumInsideInternalStruct.a
-  ---
+
   -> let privateNestedInsidePrivate = PrivateStruct.PrivateEnumInsidePrivateStruct.a
   -> let automaticNestedInsidePrivate = PrivateStruct.AutomaticEnumInsidePrivateStruct.a
-  ---
+
   !$ error: 'PrivateEnumInsidePublicStruct' is inaccessible due to 'private' protection level
   !! let privateNestedInsidePublic = PublicStruct.PrivateEnumInsidePublicStruct.a
   !!                                              ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
@@ -615,14 +615,14 @@ you must explicitly declare the nested type as public.
   -> let internalNestedInsidePublic = PublicStruct.InternalEnumInsidePublicStruct.a
   -> let automaticNestedInsidePublic = PublicStruct.AutomaticEnumInsidePublicStruct.a
   -> let privateNestedInsidePublic = PublicStruct.PrivateEnumInsidePublicStruct.a
-  ---
+
   -> let internalNestedInsideInternal = InternalStruct.InternalEnumInsideInternalStruct.a
   -> let automaticNestedInsideInternal = InternalStruct.AutomaticEnumInsideInternalStruct.a
   -> let privateNestedInsideInternal = InternalStruct.PrivateEnumInsideInternalStruct.a
-  ---
+
   -> let privateNestedInsidePrivate = PrivateStruct.PrivateEnumInsidePrivateStruct.a
   -> let automaticNestedInsidePrivate = PrivateStruct.AutomaticEnumInsidePrivateStruct.a
-  ---
+
   !$ error: 'InternalEnumInsidePublicStruct' is inaccessible due to 'internal' protection level
   !! let internalNestedInsidePublic = PublicStruct.InternalEnumInsidePublicStruct.a
   !!                                               ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
@@ -701,7 +701,7 @@ internal class B: A {
   -> public class A {
         fileprivate func someMethod() {}
      }
-  ---
+
   -> internal class B: A {
         override internal func someMethod() {}
      }
@@ -734,7 +734,7 @@ internal class B: A {
   -> public class A {
         fileprivate func someMethod() {}
      }
-  ---
+
   -> internal class B: A {
         override internal func someMethod() {
            super.someMethod()
@@ -1162,7 +1162,7 @@ on any type that adopts the protocol.
         var publicProperty = 0
         func publicMethod() {}
      }
-  ---
+
   -> public class PublicClassConformingToInternalProtocol: InternalProtocol {
         var internalProperty = 0
         func internalMethod() {}
@@ -1190,7 +1190,7 @@ on any type that adopts the protocol.
   !$ error: cannot find type 'FilePrivateProtocol' in scope
   !! public class PublicClassConformingToFilePrivateProtocol: FilePrivateProtocol {
   !! ^~~~~~~~~~~~~~~~~~~
-  ---
+
   // these will fail, because PrivateProtocol isn't visible outside of its file
   -> public class PublicClassConformingToPrivateProtocol: PrivateProtocol {
         var privateProperty = 0
@@ -1440,7 +1440,7 @@ extension SomeStruct: SomeProtocol {
   -> struct SomeStruct {
          private var privateVariable = 12
      }
-  ---
+
   -> extension SomeStruct: SomeProtocol {
          func doSomething() {
              print(privateVariable)
@@ -1474,19 +1474,19 @@ but a public type alias can't alias an internal, file-private, or private type.
   -> public struct PublicStruct {}
   -> internal struct InternalStruct {}
   -> private struct PrivateStruct {}
-  ---
+
   -> public typealias PublicAliasOfPublicType = PublicStruct
   -> internal typealias InternalAliasOfPublicType = PublicStruct
   -> private typealias PrivateAliasOfPublicType = PublicStruct
-  ---
+
   -> public typealias PublicAliasOfInternalType = InternalStruct     // not allowed
   -> internal typealias InternalAliasOfInternalType = InternalStruct
   -> private typealias PrivateAliasOfInternalType = InternalStruct
-  ---
+
   -> public typealias PublicAliasOfPrivateType = PrivateStruct       // not allowed
   -> internal typealias InternalAliasOfPrivateType = PrivateStruct   // not allowed
   -> private typealias PrivateAliasOfPrivateType = PrivateStruct
-  ---
+
   !$ error: type alias cannot be declared public because its underlying type uses an internal type
   !! public typealias PublicAliasOfInternalType = InternalStruct     // not allowed
   !! ^                           ~~~~~~~~~~~~~~

TSPL.docc/LanguageGuide/AdvancedOperators.md

@@ -701,7 +701,7 @@ extension Vector2D {
   -> struct Vector2D {
         var x = 0.0, y = 0.0
      }
-  ---
+
   -> extension Vector2D {
          static func + (left: Vector2D, right: Vector2D) -> Vector2D {
             return Vector2D(x: left.x + right.x, y: left.y + right.y)
@@ -1028,7 +1028,7 @@ let afterDoubling = +++toBeDoubled
            return vector
         }
      }
-  ---
+
   -> var toBeDoubled = Vector2D(x: 1.0, y: 4.0)
   -> let afterDoubling = +++toBeDoubled
   /> toBeDoubled now has values of (\(toBeDoubled.x), \(toBeDoubled.y))
@@ -1349,7 +1349,7 @@ print(personalGreeting.draw())
   -> func caps(@DrawingBuilder content: () -> Drawable) -> Drawable {
          return AllCaps(content: content())
      }
-  ---
+
   -> func makeGreeting(for name: String? = nil) -> Drawable {
          let greeting = draw {
              Stars(length: 3)
@@ -1369,7 +1369,7 @@ print(personalGreeting.draw())
   -> let genericGreeting = makeGreeting()
   -> print(genericGreeting.draw())
   <- ***Hello WORLD!**
-  ---
+
   -> let personalGreeting = makeGreeting(for: "Ravi Patel")
   -> print(personalGreeting.draw())
   <- ***Hello RAVI PATEL!**
@@ -1539,7 +1539,7 @@ see <doc:Attributes#resultBuilder>.
          // static func * (scale: Double, vector: Self) -> Self
          static func *** (scale: Double, vector: Vector2D) -> Vector2D
      }
-  ---
+
   -> extension Double {
          static func *** (scale: Double, vector: Vector2D) -> Vector2D {
              return Vector2D(x: scale * vector.x, y: scale * vector.y)