Currently rules_rust requires the user to override the protoc compiler

However Bazel 7 introduced --incompatible_enable_proto_toolchain_resolution and rules_proto 6.0 allows users to register a toolchain for protoc. The toolchain_type is @rules_proto//proto:toolchain_type: https://github.com/bazelbuild/rules_proto/blob/6.0.0-rc3/proto/BUILD#L57-L60

https://registry.bazel.build/modules/toolchains_protoc is a reference implementation and has examples

Similar change in other language rules:

• python: refactor: toolchainize py_proto_library bazel-contrib/rules_python#1577
• go: Support --incompatible_enable_proto_toolchain_resolution bazel-contrib/rules_go#3895