sqf: invalid comparisons

[BrettMayson]

There may still be false positives, but I didn't find any with the few repos I have locally
There may be false negatives, but I think that's ok

[PabstMirror]

didn't see any hits on my repos

[codecov]

Codecov Report

Attention: Patch coverage is 71.32616% with 80 lines in your changes missing coverage. Please review.

Project coverage is 68.2%. Comparing base (015cbf5) to head (613f24e).
Report is 2 commits behind head on main.

Files with missing lines	Patch %	Lines
...s/sqf/src/analyze/lints/s21_invalid_comparisons.rs	71.2%	80 Missing ⚠️

Additional details and impacted files

Files with missing lines	Coverage Δ
libs/sqf/src/analyze/lints/s18_in_vehicle_check.rs	73.3% <100.0%> (ø)
...s/sqf/src/analyze/lints/s21_invalid_comparisons.rs	71.2% <71.2%> (ø)

... and 3 files with indirect coverage changes