[kotlin] add additionalEnumTypeAnnotations option
Fixes #24978.
AbstractKotlinCodegen implements only additionalModelTypeAnnotations, and kotlin-server/libraries/jaxrs-spec/enum_class.mustache includes that partial, so an annotation valid only on classes is emitted on generated enums too and the output does not compile.
This adds additionalEnumTypeAnnotations to AbstractKotlinCodegen, mirroring AbstractJavaCodegen, and switches the jaxrs-spec enum template to it.
New test in KotlinServerCodegenTest: with both options set, the enum carries only the enum annotation and the data class only the model annotation. On master it fails at the first assertion (Type.kt does not contain line [@EnumOnlyAnnotation]).
./bin/generate-samples.sh bin/configs/kotlin*.yaml produces no sample changes; generator docs are regenerated.
Summary by cubic
Fixes #24978. additionalModelTypeAnnotations was applied to generated Kotlin enums too, causing compilation failures for annotations valid only on classes.
Adds additionalEnumTypeAnnotations to AbstractKotlinCodegen and switches the kotlin-server jaxrs-spec enum template to use it, so enum and model annotations stay separate.
- Regenerates generator docs for the Kotlin generators, including
ktorm-schema. - New test verifies enums receive only the enum annotation and data classes only the model annotation.