OpenAPI 3 with discriminator & mapping fields

Hi,

Firstly, congratulations for your tool. It is really the best viewer that I could have used!

From redoc v2.0.0-rc.18, I have a problem with discriminator & mapping fields of OpenAPI 3
Indeed, below, we can see my screenshot from the following specs file:

openapi: 3.0.0

########## INFO ##########
info:
  title: Test
  description: Specifications of test bounded context
  version: 1.0.0

paths:
  /pet:
    put:
      tags:
      - Pet
      description: Test
      requestBody:
        content:
          application/json:
            schema:
              $ref: "#/components/schemas/Pet"
        description: Capture that has to be applied to transaction
      responses:
        "200":
          description: The transaction captured.
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/Pet"
components:
  schemas:
    Pet:
      type: object
      required:
      - pet_type
      properties:
        pet_type:
          type: string
      discriminator:
        propertyName: pet_type
        mapping:
          dog: "Dog"
          cat: "Cat"
          lizard: "Lizard"
    Dog:
      allOf:
      - $ref: "#/components/schemas/Pet"
      - type: object
        # all other properties specific to a `Dog`
        properties:
          bark:
            type: string
    Cat:
      allOf:
      - $ref: "#/components/schemas/Pet"
      - type: object
        # all other properties specific to a `Cat`
        properties:
          name:
            type: string
    Lizard:
      allOf:
      - $ref: "#/components/schemas/Pet"
      - type: object
        # all other properties specific to a `Lizard`
        properties:
          lovesRocks:
            type: boolean

The issue provides an OpenAPI 3 schema example and a screenshot, but names no repository file, test, or entry point. Reproduce the example in the Redoc viewer and investigate how discriminator and mapping fields are rendered; done should be defined by the expected rendering, which the issue does not specify.