Disallow fragments in some uri-references

This should also apply to $self, when it is added.

Author: karenetheridge

schemas/v3.1/schema.yaml

@@ -11,8 +11,7 @@ properties:
   info:
     $ref: '#/$defs/info'
   jsonSchemaDialect:
-    type: string
-    format: uri-reference
+    $ref: '#/$defs/uri-reference-no-fragment'
     default: 'https://spec.openapis.org/oas/3.1/dialect/WORK-IN-PROGRESS'
   servers:
     type: array
@@ -972,3 +971,9 @@ $defs:
       properties:
         explode:
           default: false
+
+  uri-reference-no-fragment:
+    $comment: a uri-reference used to reference an entire document, not a position in an OpenAPI description
+    type: string
+    format: uri-reference
+    regex: '^[^#]*$'