feat: support enum names and descriptions

[sapphi-red]

Description

Added support for x-enum-varnames / x-enumNames and x-enum-descriptions.

Motivation and Context

x-enumNames are supported by NSwag (docs).
Also x-enum-varnames/x-enum-descriptions are supported by openapi-generator (docs).

These values can be used for providing names or descriptions for each enum values.
It would be great if it is shown also with Swagger UI.

Refs #5272 (This PR does not change dropdowns so it will not fix this issue)

How Has This Been Tested?

Ran npm run dev and checked the behavior with the urls below.

• https://petstore.swagger.io/v2/swagger.json: without any x-enumNames or x-enum-varnames or x-enum-descriptions
• https://raw.githubusercontent.com/traPtitech/traQ/master/docs/v3-api.yaml: with x-enum-varnames and x-enum-descriptions

Screenshots (if appropriate):

Without any x-enumNames or x-enum-varnames or x-enum-descriptions

With x-enum-varnames and x-enum-descriptions

Checklist

My PR contains...

• No code changes (src/ is unmodified: changes to documentation, CI, metadata, etc.)
• Dependency changes (any modification to dependencies in package.json)
• Bug fixes (non-breaking change which fixes an issue)
• Improvements (misc. changes to existing features)
• Features (non-breaking change which adds functionality)

My changes...

• are breaking changes to a public API (config options, System API, major UI change, etc).
• are breaking changes to a private API (Redux, component props, utility functions, etc.).
• are breaking changes to a developer API (npm script behavior changes, new dev system dependencies, etc).
• are not breaking changes.

Documentation

• My changes do not require a change to the project documentation.
• My changes require a change to the project documentation.
• If yes to above: I have updated the documentation accordingly.

I am not sure whether this should be documented.

Automated tests

• My changes can not or do not need to be tested.
• My changes can and should be tested by unit and/or integration tests.
• If yes to above: I have added tests to cover my changes.
• If yes to above: I have taken care to cover edge cases in my tests.
• All new and existing tests passed.

I am not sure whether this change is needed to be tested.

[tim-lai]

@sapphi-red Thanks for the PR! Although useful, this vendor specific feature would be better as a separate plugin, that is maintained outside of the SwaggerUI project.

[sapphi-red]

OK. Thanks for the response.

P.S. I have published a plugin.
https://github.com/sapphi-red/swagger-ui-plugin-enum-names