More full support of raw identifiers

[fzyzcjy]

Changes

Close #2346

Checklist

• [ ] An issue to be fixed by this PR is listed above.
• [ ] New tests are added to ensure new features are working. Please refer to this page to see how to add a test.
• [ ] ./frb_internal precommit --mode slow (or fast) is run (it internal runs code generator, does auto formatting, etc).
• [ ] If this PR adds/changes features, documentations (in the ./website folder) are updated.
• [ ] CI is passing. Please refer to this page to see how to solve a failed CI.

Remark for PR creator

• ./frb_internal --help shows utilities for development.
• If fzyzcjy does not reply for a few days, maybe he just did not see it, so please ping him.

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 98.88889% with 1 line in your changes missing coverage. Please review.

Project coverage is 97.54%. Comparing base (648c239) to head (0dd8486). Report is 57 commits behind head on master.

Files with missing lines	Patch %	Lines
...dart/spec_generator/class/ty/enumeration_simple.rs	0.00%	1 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #2391 +/- ## ========================================== - Coverage 98.92% 97.54% -1.39% ========================================== Files 494 472 -22 Lines 20365 18717 -1648 ========================================== - Hits 20146 18257 -1889 - Misses 219 460 +241 ```

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