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>

crates/ruff_python_formatter/generate.py

@@ -24,7 +24,7 @@ nodes_file = (
     root.joinpath("crates")
     .joinpath("ruff_python_ast")
     .joinpath("src")
-    .joinpath("node.rs")
+    .joinpath("generated.rs")
     .read_text()
 )
 node_lines = (