Support `self` in non-opaque case (`&self` already supported before); Support `&SomeStructOrEnum` in non-opaque case (`SomeStructOrEnum` already supported before); Support `&str` type (`String` already supported before)

[fzyzcjy]

Changes

Close #1871

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

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 97.26%. Comparing base (e0baf4b) to head (383424d).

:exclamation: Current head 383424d differs from pull request most recent head d438782. Consider uploading reports for the commit d438782 to get more accurate results

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #1880 +/- ## ========================================== - Coverage 99.27% 97.26% -2.01% ========================================== Files 365 361 -4 Lines 15454 14096 -1358 ========================================== - Hits 15342 13711 -1631 - Misses 112 385 +273 ```

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