[BUG][Asciidoc] converter replaces underscore with CamelCase

Bug Report Checklist

• Have you provided a full/minimal spec to reproduce the issue?
• Have you validated the input using an OpenAPI validator (example)?
• What's the version of OpenAPI Generator used? 4.2.1
• Have you search for related issues/PRs?

Description

When a component schema contains a _ in the name, this is replaced with a camel cased version.
Unfortunately this is not consistent and most anchors are rendered correctly but therefore don't follow the reference since the target does not contain the underscore

openapi-generator version

4.2.1

OpenAPI declaration file content or url

openapi: 3.0.1
info:
  title: Swagger Petstore
  version: "1.0.0"
paths:
  /pet/{petId}:
    get:
      tags:
        - pet
      summary: Find pet by ID
      description: Returns a single pet
      operationId: getPetById
      parameters:
        - name: petId
          in: path
          description: ID of pet to return
          required: true
          schema:
            type: integer
            format: int64
      responses:
        200:
          description: successful operation
          content:
            application/xml:
              schema:
                $ref: '#/components/schemas/My_Pet'
            application/json:
              schema:
                $ref: '#/components/schemas/My_Pet'
components:
  schemas:
    Main_Category:
      type: object
      properties:
        id:
          type: integer
          format: int64
        name:
          type: string
      xml:
        name: Main_Category
    My_Pet:
      type: object
      properties:
        id:
          type: integer
          format: int64
        category:
          $ref: '#/components/schemas/Main_Category'
      xml:
        name: My_Pet

Start with the supplied OpenAPI declaration and the Asciidoc converter's handling of schema names, anchors, and references. Reproduce the issue with the Main_Category and My_Pet schemas, then trace where underscores are transformed. Done means generated anchors and references consistently preserve or resolve the schema names.