Finally remove the dougthor42/go-tree-sitter fork, fixing #2630.

Admittedly we could have done this sooner had I figured things
out sooner... but c'est la vie.

Instead of using the BUILD.bazel files in dougthor42/go-tree-sitter,
we basically vendor the build file via http_archive.

This is different than using patches because non-root Bazel modules
can still make use of the BUILD.bazel files we make.

Background:

The reason we migrated to dougthor42/go-tree-sitter in the first
place was to support python 3.12 grammar. smacker/go-tree-sitter
supported for python 3.12, but made a change to their file structure
that Gazelle was unable to handle. Specifically, the
python/binding.go file indirectly requires a c header file found
in a parent directory, and Gazelle doesn't know how to handle that
for go_repository (WORKSPACE) and go_deps.from_file (bzlmod).

So dougthor42/go-tree-sitter created our own BUILD.bazel files
that included the required filegroups and whatnot, thus negating
the need for Gazelle to generate BUILD.bazel files.

Future Work:

This still doesn't resolve the issues with bumping rules_go and go
seen in #2962, but it does simplify that investigation a bit as
it's just one fewer thing to account for. It also doesn't address
the desire to migrate to the official tree-sitter/go-tree-sitter
repo, but @jbedard found some perf issues with that anyway
(tree-sitter/go-tree-sitter#32).