parse: fix // inside single quote strings

[PabstMirror]

e.g. url inside single quote string

error[SPE1]: invalid token
1 │ _ctrl htmlLoad 'https://zombo.com/';
  │                      ^ invalid token

the // was treated as a comment and the rest of line was cutoff (so just 'https:)

I am not positive on my change to parsing logic and changes should be carefully looked it,
but it seems to pass all tests

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 68.8%. Comparing base (21b2b2e) to head (8023a3d).

Additional details and impacted files

Files	Coverage Δ
libs/preprocessor/src/parse/mod.rs	94.6% <100.0%> (+0.2%)	⬆️

... and 6 files with indirect coverage changes