Static instance parameters (#48056)

* Update access-modifiers.md

Added description for file access type modifier

* Update Program.cs

Add an example to show parameterless static and instance constructors in a single class.

* Update constructors.md

Mention Static and instance constructor definiton

Author: bigboybamo

docs/csharp/programming-guide/classes-and-structs/constructors.md

@@ -56,6 +56,10 @@ You can also define a static constructor with an expression body definition, as
 
 For more information and examples, see [Static Constructors](./static-constructors.md).
 
+A class can also have **both** an Instance and Static constructor defined, and they can each be defined without parameters.
+
+:::code source="./snippets/constructors/Program.cs" id="DualConstructor":::
+
 ## Partial constructors
 
 Beginning with C# 14, you can declare *partial constructors* in a partial class or struct. Any partial constructor must have a *defining declaration* and an *implementing declaration*. The signatures of the declaring and implementing partial constructors must match according to the rules of [partial members](./partial-classes-and-methods.md#partial-members). The defining declaration of the partial constructor can't use the `: base()` or `: this()` constructor initializer. You add any constructor initializer must be added on the implementing declaration.

docs/csharp/programming-guide/classes-and-structs/snippets/constructors/Program.cs

@@ -72,3 +72,20 @@ public required T Contents
 }
 // </PrimaryCtor>
 
+// <DualConstructor>
+public class Example
+{
+    static Example()
+    {
+        Console.WriteLine("Static constructor called.");
+    }
+    
+    public Example()
+    {
+        Console.WriteLine("Instance constructor called.");
+    }
+
+    // Remaining implementation of Child class.
+}
+// </DualConstructor>
+