rust_analyzer repository registered multiple times

I'm trying to register multiple toolchains with bzlmod (they have different settings, omitted here for simplicity):

```
rust.toolchain(
edition = "2024",
target_settings = [ "@rules_rust//rust/platform:x86_64-apple-darwin" ],
versions = ["1.90.0"],
)

rust.toolchain(
edition = "2024",
target_settings = [ "@rules_rust//rust/platform:aarch64-apple-darwin" ],
versions = ["1.90.0"],
)

...
```

Unfortunately this leads to an error:

> A repo named rust_analyzer_1.90.0_tools is already generated by this module extension

I think the `maybe()` call is incorrect, and should be applied to the repository:

```diff
diff --git a/rust/repositories.bzl b/rust/repositories.bzl
index 71305a752..b9e21ca88 100644
--- a/rust/repositories.bzl
+++ b/rust/repositories.bzl
@@ -238,8 +238,7 @@ def rust_register_toolchains(
exec_compatible_with_by_toolchain = {}
target_compatible_with_by_toolchain = {}

- maybe(
- rust_analyzer_toolchain_repository,
+ rust_analyzer_toolchain_setup(
name = rust_analyzer_repo_name,
version = rust_analyzer_version,
urls = urls,
@@ -838,7 +837,7 @@ rust_analyzer_toolchain_tools_repository = repository_rule(
attrs = _RUST_ANALYZER_TOOLCHAIN_TOOLS_REPOSITORY_ATTRS,
)

-def rust_analyzer_toolchain_repository(
+def rust_analyzer_toolchain_setup(
name,
version,
exec_compatible_with = [],
@@ -866,7 +865,8 @@ def rust_analyzer_toolchain_repository(
Returns:
str: The name of a registerable rust_analyzer_toolchain.
"""
- rust_analyzer_toolchain_tools_repository(
+ maybe(
+ rust_analyzer_toolchain_tools_repository,
name = name + "_tools",
version = version,
sha256s = sha256s,
```

This however I believe only works for `WORKSPACE`. Even with the fix above, the error is still present when importing rules_rust via `MODULE.bazel`