fix: bzlmod users don't need to register toolchain

The toolchains_protoc MODULE file registers the protoc toolchain itself.

Author: alexeagle

.github/workflows/release_prep.sh

@@ -22,20 +22,16 @@ cat << EOF
 2. Add to your \`MODULE.bazel\` file:
 
 \`\`\`starlark
+# NB: this must come BEFORE bazel_dep(name = "protobuf") because they register the from-source toolchain,
+# and the first registration wins.
 bazel_dep(name = "toolchains_protoc", version = "${TAG:1}")
 
 # Optional: choose a version of protoc rather than the latest.
 protoc = use_extension("@toolchains_protoc//protoc:extensions.bzl", "protoc")
 protoc.toolchain(
-    # Creates a repository to satisfy well-known-types dependencies such as
-    # deps=["@com_google_protobuf//:any_proto"]
-    google_protobuf = "com_google_protobuf",
     # Pin to any version of protoc
     version = "v26.0",
 )
-use_repo(protoc, "com_google_protobuf", "toolchains_protoc_hub")
-
-register_toolchains("@toolchains_protoc_hub//:all")
 \`\`\`
 
 ## Using WORKSPACE

examples/.bazelrc

@@ -7,6 +7,8 @@ common --host_platform=//tools:no_cgo_host_platform
 common --@aspect_rules_ts//ts:skipLibCheck=always
 common --@aspect_rules_ts//ts:default_to_tsc_transpiler
 
+common --java_runtime_version=remotejdk_11
+
 # Ensure that we don't accidentally build protobuf or gRPC
 common --per_file_copt=external/.*protobuf.*@--PROTOBUF_WAS_NOT_SUPPOSED_TO_BE_BUILT
 common --host_per_file_copt=external/.*protobuf.*@--PROTOBUF_WAS_NOT_SUPPOSED_TO_BE_BUILT

examples/MODULE.bazel

@@ -37,9 +37,7 @@ protoc.toolchain(
     # Demonstrate overriding the default version
     version = "v28.0",
 )
-use_repo(protoc, "com_google_protobuf", "toolchains_protoc_hub")
-
-register_toolchains("@toolchains_protoc_hub//:all")
+use_repo(protoc, "com_google_protobuf")
 
 # NB: the `:all` here is critical, because `proto_lang_toolchain` expands into two targets:
 # - proto_lang_toolchain rule [name]