minor simplification of v3.1 schema (#2671)

* minor simplification of v3.1 schema

"if the X property is present, then apply this constraint to property X" can
be simplified by simply stating the constraint for property X.

* add missing constraint to "header"

https://spec.openapis.org/oas/v3.1.0#headerObject

* allowEmptyValue and allowReserved don't make sense for headers

* collapse single-item "enum"s in "cookie" and "header" to "const"

Author: karenetheridge

schemas/v3.1/schema.json

@@ -534,9 +534,7 @@
                 "properties": {
                   "style": {
                     "default": "simple",
-                    "enum": [
-                      "simple"
-                    ]
+                    "const": "simple"
                   }
                 }
               }
@@ -581,9 +579,7 @@
                 "properties": {
                   "style": {
                     "default": "form",
-                    "enum": [
-                      "form"
-                    ]
+                    "const": "form"
                   }
                 }
               }
@@ -934,40 +930,38 @@
           "default": false,
           "type": "boolean"
         },
-        "allowEmptyValue": {
-          "default": false,
-          "type": "boolean"
+        "schema": {
+          "$dynamicRef": "#meta"
+        },
+        "content": {
+          "$ref": "#/$defs/content"
         }
       },
+      "oneOf": [
+        {
+          "required": [
+            "schema"
+          ]
+        },
+        {
+          "required": [
+            "content"
+          ]
+        }
+      ],
       "dependentSchemas": {
         "schema": {
           "properties": {
             "style": {
               "default": "simple",
-              "enum": [
-                "simple"
-              ]
+              "const": "simple"
             },
             "explode": {
               "default": false,
               "type": "boolean"
-            },
-            "allowReserved": {
-              "default": false,
-              "type": "boolean"
-            },
-            "schema": {
-              "$dynamicRef": "#meta"
             }
           },
           "$ref": "#/$defs/examples"
-        },
-        "content": {
-          "properties": {
-            "content": {
-              "$ref": "#/$defs/content"
-            }
-          }
         }
       },
       "$ref": "#/$defs/specification-extensions",

schemas/v3.1/schema.yaml

@@ -363,8 +363,7 @@ $defs:
               properties:
                 style:
                   default: simple
-                  enum:
-                    - simple
+                  const: simple
 
           styles-for-query:
             if:
@@ -394,8 +393,7 @@ $defs:
               properties:
                 style:
                   default: form
-                  enum:
-                    - form
+                  const: form
 
           styles-for-form:
             if:
@@ -634,29 +632,25 @@ $defs:
       deprecated:
         default: false
         type: boolean
-      allowEmptyValue:
-        default: false
-        type: boolean
+      schema:
+        $dynamicRef: '#meta'
+      content:
+        $ref: '#/$defs/content'
+    oneOf:
+      - required:
+        - schema
+      - required:
+        - content
     dependentSchemas:
       schema:
         properties:
           style:
             default: simple
-            enum:
-              - simple
+            const: simple
           explode:
             default: false
             type: boolean
-          allowReserved:
-            default: false
-            type: boolean
-          schema:
-            $dynamicRef: '#meta'
         $ref: '#/$defs/examples'
-      content:
-        properties:
-          content:
-            $ref: '#/$defs/content'
     $ref: '#/$defs/specification-extensions'
     unevaluatedProperties: false