Committing in Materialize

Read doc/developer/guide-changes.md for the full conventions on submitting and reviewing changes.

Pre-commit checklist

Before committing, run these and fix any warnings:

1. bin/fmt (formats .rs, .py, and .proto files)
2. bin/lint (can error if tools are missing; use bin/ci-builder run stable bin/lint as an alternative)
3. cargo clippy --all-targets -- -D warnings

Do not manually update *.snap files. Use cargo test followed by cargo insta accept to update snapshot files. Rewrite datadriven test expectations with REWRITE=1 cargo test ....

PR titles and commit messages

Materialize uses squash merging, so the PR title becomes the commit subject on main.