* The ungram file is now taken from the rust-analyzer dependencies
pulled in by bazel
* the grammar parsing code is not published, so it must be taken
directly from rust-analyzer code. That part should be less prone to be
updated than the ungram file, so it does not necessarily need to be
in sync with the rust-analyzer version is used elsewhere.
* both need some patches. The former is patched during build, the latter
during loading in `MODULE.bazel`.
This passes command line arguments to codegen, allowing in particular
`--force` to be passed.
Also, a convenience `//rust/codegen:py` is added to only run the python
based code generation, which will be faster and enough when
`ast-generator` is unchanged.
We've hardcoded the tilde in a lot of places :(
This improves performance on Windows and gets us ready for Bazel 8.
We need an upgrade of rules_rust for this to work.
