Fix globs in .gitignore and add more patterns.

[mhucka]

Changes:

• Patterns like .mypy_cache/* did not match in subdirectories. Fixed.
• Added .ruff_cache/ because we're beginning to use ruff.
• Added patterns for miscellaneous editor backup & checkpoint files.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 99.63%. Comparing base (9888067) to head (e04feac).

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #7992      +/-   ##
==========================================
- Coverage   99.63%   99.63%   -0.01%     
==========================================
  Files        1110     1110              
  Lines       99685    99685              
==========================================
- Hits        99318    99317       -1     
- Misses        367      368       +1     

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