Bug: strip comments=True leaves the last comment when a query contains only comments

Bug: strip comments=True leaves the last comment when a query contains only comments: a task in repo2rlenv-swe-next (Harbor dataset). When formatting a SQL string that consists entirely of single-line comments (e.g., --A;\n--B; ), using strip comments=True should return an empty string. Instead…

The task

When formatting a SQL string that consists entirely of single-line comments (e.g., `--A;\n--B;`), using `strip_comments=True` should return an empty string. Instead, the last comment is left in the output.

Part of FineEnvs/repo2rlenv-swe-next.