Deprecate literal computed property names in enums - #64358

TypeScript already reports “Computed property names are not allowed in enums.” However, it makes an exception for string literals and template literals without substitutions. As Anders noted in the issue, disallowing computed names altogether would match the intent of the existing diagnostic, but compatibility is a concern.

The accepted forms do not add expressive power: single-quoted strings, double-quoted strings, and template literals without substitutions can all be written as ordinary string literal member names. References to variables and expressions such as ["a" + "b"] are already rejected.

For example:

enum Example {
    ['first'],
    ["second"],
    [`third`],
}

// Equivalent string literal names:
enum Example {
    'first',
    "second",
    "third",
}

This PR provides a gradual migration path without introducing new compilation errors. It adds a deprecation suggestion for the accepted computed names and a quick fix to convert them to ordinary string literals. Individual fixes, Fix All, and source.fixAll are supported, with decoded member names preserved.

Names that already produce errors retain their existing diagnostics without an additional deprecation suggestion. Tests cover these cases, individual and batch fixes, and escaped and multiline literal contents.

• Fixes Enum declarations should consistently disallow computed keys #42468
• Previous proposal: Add deprecation warning for computed property names in enums #62818