spring-mvc generator prefixes String in enum when using "modelNamePrefix" or "modelNameSuffix"

Description

spring-mvc generator prefixes String in enum when using "modelNamePrefix" or "modelNameSuffix"
which leads to compile errors.

openapi-generator version

			<groupId>org.openapitools</groupId>
			<artifactId>openapi-generator-maven-plugin</artifactId>
			<version>3.3.4</version>

OpenAPI declaration file content or url

create some enum like:
Version:
type: String
enum:
- 2.1.0
- 2.2.0

Command line used for generation

Steps to reproduce

					<configuration>
						<inputSpec>${project.basedir}/src/main/resources/openapi-3ds.yaml</inputSpec>
						<output>${project.build.directory}/generated-sources/openapi</output>
						<generatorName>spring</generatorName>
						<modelPackage>de.restapi.openapi.model</modelPackage>
						<apiPackage>de.restapi.openapi</apiPackage>
						<modelNamePrefix>OA</modelNamePrefix>
						<configOptions>
							<sourceFolder>openapi</sourceFolder>
							<library>spring-mvc</library>
							<interfaceOnly>true</interfaceOnly>
							<useBeanValidation>true</useBeanValidation>
							<dateLibrary>java8</dateLibrary>
							<java8>true</java8>
							<useTags>true</useTags>
						</configOptions>

Related issues/PRs

Suggest a fix/enhancement

i guess you need to exclude some class types from being prefixed.. like anythign from the JDK...

Reproduce the issue with the spring generator, spring-mvc library, and modelNamePrefix or modelNameSuffix configuration shown in the report. Inspect the generator's model-name handling and generated enum output, then verify that JDK type names are not incorrectly prefixed and that the generated Java compiles.