openapi-generator-maven-plugin syntax errors for range codes, e.g. 4XX

Description

We use the following dependencies:

For annotations

		<dependency>
		<groupId>io.swagger.parser.v3</groupId>
		<artifactId>swagger-parser</artifactId>
		<version>2.0.24</version>
		</dependency>

For generation:

	<plugin>
		<groupId>org.openapitools</groupId>
		<artifactId>openapi-generator-maven-plugin</artifactId>
		<version>5.1.0</version>
		<executions>
...
	</plugin>

We use a range definition (4XX) as to OpenAPI v3 specification for response codes, this generates the following code, which has a syntax error in it:

openapi-generator version

5.1.0

OpenAPI declaration file content or url

If you post the code inline, please wrap it with

...
      responses:
        "4XX":
          description: Error
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/error'
...

Command line used for generation

using the openapi maven generator plugin:
java

Steps to reproduce

generate with a range response code

Related issues/PRs

Somehow this should have been solved with https://github.com/OpenAPITools/openapi-generator/pull/7854 , although I do not understand how & it does not seem to work.

Start with the OpenAPI response definition using the "4XX" range and the Java generator entry point invoked by openapi-generator-maven-plugin. Review the related PR 7854 and reproduce generation with the supplied declaration; done means the generated Java output is syntactically valid for range response codes.