[csharp] Introducing the enumPropertyNaming option to the C# Generator

[fujieda]

This pull request introduces the enumPropertyNaming option to the C# generator. This option, which is currently supported by the Kotlin and TypeScript generators, allows you to control the naming style of enum names.

In our projects, we consistently use UPPER_SNAKE_CASE for constants in our OpenAPI definitions, and we prefer to maintain this naming style in our C# code. However, the current C# generator changes the enum names by removing the underscores, resulting in enum names like UPPERSNAKECASE.

While searching for a solution to this problem, I came across the enumPropertyNaming option available in the Kotlin and TypeScript generators. To resolve this discrepancy and ensure that our enum naming style remains consistent with UPPER_SNAKE_CASE, I ported this option to the C# generator.

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[wing328]

@fujieda thanks for the PR.

What about adding an option similar to modelNameMapping, parameterNameMapping such as enumNameMapping to have complete control of the enum naming in the C# generator?

ref: https://github.com/OpenAPITools/openapi-generator/blob/master/docs/customization.md#name-mapping

[fujieda]

@wing328

I couldn't find an option to define enum name mappings similar to modelNameMapping and parameterNameMapping in the C# generator. Upon reviewing the toEnumVarName method in AbstractCsharpCodegen, it appears that there's no code implementation for applying name mappings, unlike toVarName, toParamName, and toModelName, which support such mappings.

However, in our projects, our primary goal is not to establish specific name mappings, but rather to exert control over the naming styles of enum names. We have a significant number of enum names within our OpenAPI definitions, over fifty in total. Given this scale, defining individual name mappings for each enum name isn't a practical or feasible approach for us.

[wing328]

I couldn't find an option to define enum name mappings similar to modelNameMapping and parameterNameMapping in the C# generator.

Sorry I wasn't clear. I mean "adding an option" to your requirement (which means the option doesn't exist yet)

Thanks for sharing the use cases. I'll review and get back to you.

[wing328]

we will try to fix that in another PR.

[wing328]

LGTM. Let's give it a try.

Thanks again for the PR.