Auto-generate AST boilerplate (#15544)

This PR replaces most of the hard-coded AST definitions with a
generation script, similar to what happens in `rust_python_formatter`.
I've replaced every "rote" definition that I could find, where the
content is entirely boilerplate and only depends on what syntax nodes
there are and which groups they belong to.

This is a pretty massive diff, but it's entirely a refactoring. It
should make absolutely no changes to the API or implementation. In
particular, this required adding some configuration knobs that let us
override default auto-generated names where they don't line up with
types that we created previously by hand.

## Test plan

There should be no changes outside of the `rust_python_ast` crate, which
verifies that there were no API changes as a result of the
auto-generation. Aggressive `cargo clippy` and `uvx pre-commit` runs
after each commit in the branch.

---------

Co-authored-by: Micha Reiser <micha@reiser.io>
Co-authored-by: Alex Waygood <Alex.Waygood@Gmail.com>

.github/workflows/ci.yaml

@@ -386,6 +386,12 @@ jobs:
       - name: "Install Rust toolchain"
         run: rustup component add rustfmt
       - uses: Swatinem/rust-cache@v2
+      # Run all code generation scripts, and verify that the current output is
+      # already checked into git.
+      - run: python crates/ruff_python_ast/generate.py
+      - run: python crates/ruff_python_formatter/generate.py
+      - run: test -z "$(git status --porcelain)"
+      # Verify that adding a plugin or rule produces clean code.
       - run: ./scripts/add_rule.py --name DoTheThing --prefix F --code 999 --linter pyflakes
       - run: cargo check
       - run: cargo fmt --all --check