stringtables: handle comments at block end, lowercase, escapes

[BrettMayson]

Fixes #822

[codecov]

Codecov Report

Attention: Patch coverage is 98.14815% with 1 line in your changes missing coverage. Please review.

Project coverage is 69.3%. Comparing base (829c241) to head (b277ba6).
Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
libs/stringtable/src/key.rs	87.5%	1 Missing ⚠️

Additional details and impacted files

Files with missing lines	Coverage Δ
libs/stringtable/src/lib.rs	89.9% <100.0%> (+80.1%)	⬆️
libs/stringtable/src/key.rs	13.0% <87.5%> (+7.8%)	⬆️