Fetch schema description when used for parameter

Content & configuration

Swagger/OpenAPI definition:

openapi: 3.0.0
info:
 title: Test API
 version: 1.0.0
paths:
 /foo/{user_id}:
   get:
     parameters: 
       - $ref: '#/components/parameters/user_id'
     responses:
       '200':
         description: A user
         content:
           application/json:
             schema:
               $ref: '#/components/schemas/User'
components:
 parameters:
   user_id:
     name: user_id
     in: path
     required: true
     schema:
       $ref: '#/components/schemas/UserId'   # <-------
 schemas:
   UserId:
     type: string
     description: The ID of a User
     example: abcdef
   User:
     type: object
     properties:
       id: 
         $ref: '#/components/schemas/UserId' # <-------

Is your feature request related to a problem?

The parameter is able to fetch the UserId's example but not the UserId's description

Describe the solution you'd like

The parameter's description should equal the UserId schemas' description.

Additional context

My original Stack Overflow question on defining an ID that is shared in a parameter and schema once.

https://stackoverflow.com/questions/53828430/how-to-use-the-same-definition-for-an-id-parameter-and-an-id-schema-property/53829788#53829788

Start by loading the provided OpenAPI 3.0 definition in Swagger UI and trace how the parameter reference resolves its schema metadata. Done means the user_id parameter displays the UserId schema description, “The ID of a User,” while retaining the existing example behavior.