The primary goal is to control the version of the `codespell` Python
package that we run via `uv.lock`. See also
https://github.com/jj-vcs/jj/pull/5425.
Also move the action next to the `cargo fmt` action. It might make sense
to split both of them out of `build.yml` if it gets too long, but I
think they should be next to each other since they are so similar in
spirit.
Our docs are built with MkDocs, which requires Python and several deps.
Previously those deps were managed with Poetry, which is also written in Python.
This commit replaces Poetry with `uv`, a Rust-based Python
project/package manager, and thus removes several steps from the docs
build process.
Before:
<install Python>
<install pipx>
pipx install poetry
poetry install
poetry run -- mkdocs serve
After:
<install uv>
uv run mkdocs serve