[BUG][KOTLIN] Using a $ in a string in the open api spec breaks kotlin generation.

Bug Report Checklist

• Have you provided a full/minimal spec to reproduce the issue?
• Have you validated the input using an OpenAPI validator (example)?
• Have you tested with the latest master to confirm the issue still exists?
• Have you searched for related issues/PRs?

Description

I am attempting to use a $ in my open api spec for a query param $next for example , but generating it makes the kotlin code uncompilable because the $ doesn't get escaped in the generated code. I can reproduce the same behavior by adding a $ into a documentation string as well.

openapi-generator version

6.6.0, gradle plugin, doesn't seem to be a regression.

OpenAPI declaration file content or url

info:
  contact:
    email: email@provider.com
    name: Maintainer
  description: 'This schema cannot be compiled after it is generated using the $kotlin generator because the $ is not escaped and kotlin allows you to use it as a placeholder.   Example:<br><br>
      val variable: String = "String"<br>
      printlin("Example placeholder $variable")<br><br>
    Outputs:<br>
    Example placeholder String
    '    
  title: Broken $Kotlin Schema
  version: v1.0.0
openapi: 3.0.3

servers:
  - description: The server
    url: http://url

paths:
  "/endpoint":
    get:
      operationId: brokenGet
      parameters:
        - description: Breaks the $kotlin generation because the $ is not escaped so we can't compile
          in: query
          name: "$brokenForKotlin"
          required: false
          schema:
            type: string
      responses:
        '201':
          content:
            application/json:
              schema:
                type: object
                properties:
                  "$brokenField":
                      type: string
          description: returns the status of the async request
      summary: Breaks the $kotlin generation because the $ is not escaped so we can't compile
      tags:
        - broken

Generation Details

This is broken for spring boot 3 and (kotlin-spring)

Steps to reproduce

Generate this schema, then compile the code

Related issues/PRs

• Not any that I could find

Suggest a fix

• Escape $'s when writing strings in the generated output

Start by generating the provided OpenAPI schema for the kotlin-spring target with the 6.6.0 Gradle plugin, then compile the generated code. Trace how the $ appears in generated documentation, parameter names, and fields, and ensure the generated Kotlin output compiles while preserving the source text.