fix and test for issue 1758

[gracekarina]

Fix and test for issue #1758.

Adds a validation message for parameters and headers when ref field in internal references are not being pointed at the right components tag.

[gracekarina]

@ponelat @frantuma I addressed the comments, and also did the validation in deserializer of examples, and securitySchemes, but not 100% sure it applies here.
If you have a sample of a ref example being use, and securitySchemes using the ref #/components/... please let me know, I haven't find any.
Thanks

[ponelat]

@gracekarina securitySchemas aren't referenced using $ref, instead they're referenced via the security: [] fields in operations and globally.

Here is an example of using $ref to point to an example. Not that they're not for schemas, but for response/requestBodies, i.e., examples, see: https://github.com/OAI/OpenAPI-Specification/blob/main/versions/3.0.3.md#exampleObject

openapi: 3.0.3
info:
  title: $ref of an "Example".
  version: 1.0.0
paths:
  /foo:
    get:
      description: ok
      responses:
        '200':
          description: ok
          content:
            application/json:
              schema:
                type: object
              examples:
                one:
                  $ref: '#/components/examples/Ex'
              
components:
  examples:
    Ex:
      summary: The value one.
      value: 
        one: '1'

[frantuma]

@gracekarina couple of minor comments, when addressed please merge

[frantuma]

I would detail what is the expected type, like "$ref target "+ref.textValue() +" is not of expected type pathItem");. Same applies to similar code below

[frantuma]

cdoe style, would replace meters")||ref.textVal with meters") || ref.textVal

[frantuma]

cdoe style, would replace meters")||ref.textVal with meters") || ref.textVal