Statically computes text value kind lookup table

[zslayton]

Builds on #892, the PR to port to winnow.

I thought there might be a performance boost to be had by computing the mapping from a text value's first byte to the value's kind at compile time and using a lookup table at runtime. Strangely, it didn't change the performance at all--benchmark results are identical.

I'm inclined to merge this anyway just so people don't spend time following the same line of reasoning in the future. Subjectively, it's a bit tidier.

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[codecov]

Codecov Report

Attention: Patch coverage is 63.93443% with 22 lines in your changes missing coverage. Please review.

Project coverage is 77.46%. Comparing base (0943766) to head (67d3db7).
Report is 2 commits behind head on main.

Files with missing lines	Patch %	Lines
src/lazy/text/token_kind.rs	0.00%	17 Missing ⚠️
src/lazy/expanded/mod.rs	0.00%	1 Missing and 2 partials ⚠️
src/lazy/expanded/macro_evaluator.rs	0.00%	0 Missing and 2 partials ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #894      +/-   ##
==========================================
- Coverage   77.49%   77.46%   -0.04%     
==========================================
  Files         136      137       +1     
  Lines       34247    34238       -9     
  Branches    34247    34238       -9     
==========================================
- Hits        26541    26521      -20     
- Misses       5728     5735       +7     
- Partials     1978     1982       +4     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.