fix: improve funcformat logic and remove unwanted pg_catalog prefixes

- Fixed syntax error by removing orphaned character
- Removed btrim from sqlSyntaxFunctions to prevent unwanted pg_catalog prefixes
- Added context-aware substring funcformat handling based on pg_catalog prefix
- Improved test count from 230/258 to 237/258 passing tests
- Remaining 21 failures mainly involve variadic parameter handling

Co-Authored-By: Dan Lynch <[email protected]>

Author: devin-ai-integration[bot]