[BUG] Problem with kotlin-spring modelNameSuffix

Created by: MaksimRT

Description

I have a problem with kotlin-spring generator. When I add any modelNameSuffix it adds it incorrectly.

Example: modelNameSuffix = "Dto"

data class GeneralDto (

        @JsonProperty("account") val account: StringDto? = null,

        @JsonProperty("is_action") val isAction: BooleanDto? = null
) {

}

openapi-generator version

I am using openapi-generator 4.0.0.

It isn't regression, because previous version doesn't contain this feature.

OpenAPI declaration file content

openapi: 3.0.0
info:
  title: Manager API
  version: 1.0.0    

tags:
- name: "Test"
  description: "Test"

paths:
  /:
    get:
      responses:
        '200':
          description: Ok      

components:
  schemas:  
    General:
      type: object
      properties:
        account:
          type: string
        is_action:
          type: boolean

Command to run

java -jar openapi-generator-cli-4.0.0.jar generate --input-spec kotlin-spring.yaml --generator-name kotlin-spring --model-name-suffix Dto