docs for bazel_skylib_gazelle_plugin via bzlmod

The release docs for bazel_skylib_gazelle_plugin only show how to add it as a dependency to your MODULE.bazel file, but there is more work necessary to integrate the plugin into a gazelle run.

It seems to also need something like this change to update a `gazelle` target to include it?

```patch
-load("@gazelle//:def.bzl", "gazelle")
+load("@gazelle//:def.bzl", "gazelle", "gazelle_binary")

+gazelle_binary(
+ name = "gazelle_bin",
+ languages = [
+ "@gazelle//language/bazel/visibility",
+ "@gazelle//language/proto",
+ "@gazelle//language/go",
+ "@bazel_skylib_gazelle_plugin//bzl:bzl",
+ ],
+)
+
gazelle(
name = "gazelle",
+ gazelle = ":gazelle_bin",
prefix = "founding",
)
```

But perhaps there's a better way to do it? I'm not sure.

Start with the release documentation and the existing MODULE.bazel dependency instructions, then verify how the bazel_skylib_gazelle_plugin is included in a gazelle target. Compare the proposed gazelle_binary setup with the supported integration path and document the complete configuration, including a reproducible gazelle run as the done condition.

Written by the indexing model from the issue text.