feat: remove "| string" and "| number" from enum targeted members

[kuhe]

This PR removes the open-ended union of | string and | number from shape members that targeted enums.

This improves the dev experience with the type system by

• flagging enum value typos
• potentially improving auto-complete in certain code editors
• enabling IDE-generation or manual writing of exhaustive switch statements

User guide:

• if using only JavaScript, you would not be affected by this change.
• If using existing declared enums, no change is expected.
• If using enums not declared in the generated model, such as when using an older version of a generated SDK, use the following overrides:
  • on inputs, use 'NEW_VALUE' as any.
  • on outputs, use e.g. if (output.enum as any === 'NEW_VALUE') {
  • in either case, you can also use a compiler comment to ignore any unenumerated fields
• you should still write a default branch, if only to throw an error, in any switch statement on an enum value.

[kuhe]

@github-actions
ci / Ensure TypeScript is formatted (pull_request)

there are no typescript changes in this PR