Description

This PR consists of added support for allowing users to add a x-position vendor extension for positioning sidebar items accordingly. The x-position: number can be defined at the endpoint/method level and can be used for the following scenarios:

1. Multiple methods with a defined x-position will be positioned in ascending order, followed by any other sidebar items in their original order.
2. Single method with a defined x-position will take precedence followed by other sidebar items in their original order.

Motivation and Context.

See #1147 for context.

How Has This Been Tested?

Tested by defining a x-position for the following Petstore methods:

1.  put:
      tags:
        - pet
      summary: Update an existing pet
      description: ""
      operationId: updatePet
      responses:
        "400":
          description: Invalid ID supplied
        "404":
          description: Pet not found
        "405":
          description: Validation exception
      security:
        - petstore_auth:
            - "write:pets"
            - "read:pets"
      x-position: 1
   

2.  post:
      tags:
        - pet
      summary: Updates a pet in the store with form data
      description: ""
      operationId: updatePetWithForm
      parameters:
        - name: petId
          in: path
          description: ID of pet that needs to be updated
          required: true
          schema:
            type: integer
            format: int64
      responses:
        "405":
          description: Invalid input
      security:
        - petstore_auth:
            - "write:pets"
            - "read:pets"
      x-position: 2
   

Screenshots (if appropriate)

Original sidebar item positions

Added x-position vendor extension

Types of changes

• New feature (non-breaking change which adds functionality)

Checklist

• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes if appropriate.
• All new and existing tests passed.