Create a rule to detect when another component type is referenced inside Schema

Is your feature request related to a problem? Please describe.
This is an extension of this issue - #767

There's a repeatable mistake when some other components type (for example, requestBody) is referenced inside the Schema component.

Example definition:

# openapi.yaml

openapi: 3.0.0
components:
  requestBodies:
    CreateContainer:
      content:
        application/json:
          schema:
            type: object
  schemas:
    PipeContainerCreate:
      title: PipelineContainerCreate
      allOf:
      - "$ref": "#/components/requestBodies/CreateContainer"

Describe the solution you'd like
Create a rule to detect and flag this type of mistake.

Describe alternatives you've considered
The messaging inside the spec rule was improved, but it might not be enough.

Additional context
N/a

Start by reviewing issue #767 and the existing spec rule, then use the openapi.yaml example to understand how a requestBodies reference appears inside a schema. The rule should flag references to another components type from a Schema component; verify the diagnostic against the example.