[BUG] [kotlin-spring] EnumConverterConfiguration fails to generate converter methdod for enum types which start with numerical value

Bug Report Checklist

• Have you validated the input using an OpenAPI validator?
• Have you tested with the latest master to confirm the issue still exists?
• Have you searched for related issues/PRs?
• What's the actual output vs expected output?
• [Optional] Sponsorship to speed up the bug fix or feature request (example)

Description

The issue occurs when the enum converter functions are generated for enum names that starts with digits. Identifiers cannot start with digits in Kotlin so the generator attempts to escape the name but this creates invalid syntax in the function declaration.

openapi-generator version

Introduced in 7.15.0
https://github.com/OpenAPITools/openapi-generator/commit/bfb69388aa3c443fb3e1912ee5da702e6335a86b

OpenAPI declaration file content or url

openapi: 3.1.0
info: 
  version: 1.0.0
  title: Test api
components:
  schemas: 
    123Example:
      type: string
      enum:
        - TESTING
        - TESTING_2
        - TESTING_3

Generates:

class EnumConverterConfiguration {
	@Bean(name=["org.openapitools.configuration.EnumConverterConfiguration`123Example`Converter"])
	fun &#x60;123Example&#x60;Converter(): Converter<Kotlin.String, Model123ExampleDto> {
		return object: Converter<kotlin.String, Model123ExampleDto> {
			override fun convert(source: kotling.String): Model123ExampleDto = Model123ExampleDto.forValue(source)
		}
	}
}

Suggest a fix

Prefix function name with Model if enum name starts with a number, similar to how the model classes are named

Start by locating the kotlin-spring generation logic for EnumConverterConfiguration and reproduce the issue with the provided OpenAPI schema containing the 123Example enum. Confirm the generated Kotlin has a valid converter function declaration and that the generated code compiles.