Dollar sign should be escaped in descriptions

[JeffMill]

Repro:

openapi: "3.0.0"
info:
  title: "Foo"
  version: "0.1.0"
paths:
  /streamingSearch:
    get:
      summary: No summary.
      description: |
        Example queries:
        - GET /Foo?$expand=Files&$top=10
      operationId: "main_streamingSearch_get"
      parameters:
        - name: "query"
          in: "query"
          required: true
          schema:
            title: "Query"
            type: "string"
      responses:
        '200':
          description: response description
          content:
            application/xml:
              schema:
                type: string
                format: xml

output markdown snippet:

- GET /Foo?$expand=Files&$top=10

this should escape the dollar signs i.e.

Example queries:
- GET /Foo?\$expand=Files&\$top=10

or it won't render properly - it will display GET /Foo?expand=Files&top=10 rather than GET /Foo?$expand=Files&$top=10