Fix malformed comment in format_latin.h

[Copilot]

Address review feedback on comment formatting in the ASCII character handling logic.

Changes

• Updated comment on line 142 in include/format_latin.h to properly separate the two conditional cases with correct punctuation

// Before
// ASCII character, copy as-is else // Invalid UTF-8, replace with ?

// After  
// ASCII character: copy as-is. Non-ASCII (invalid UTF-8 here), replace with '?'

---

✨ Let Copilot coding agent set things up for you — coding agent works faster and does higher quality work when set up for your repo.