No such target '@@rules_go+//go/toolchain:loongarch64'

I encountered the following problem when building bazel on a loongarch64 architecture CPU:
```
ERROR: /tmp/bazel_ZehUYc76/out/external/rules_go+/go/toolchain/BUILD.bazel: no such target '@@rules_go+//go/toolchain:loongarch64': target 'loongarch64' not declared in package 'go/toolchain' defined by /tmp/bazel_ZehUYc76/out/external/rules_go+/go/toolchain/BUILD.bazel
ERROR: /tmp/bazel_ZehUYc76/out/external/rules_go++go_sdk+go_toolchains/BUILD.bazel:9:25: no such target '@@rules_go+//go/toolchain:loongarch64': target 'loongarch64' not declared in package 'go/toolchain' defined by /tmp/bazel_ZehUYc76/out/external/rules_go+/go/toolchain/BUILD.bazel and referenced by '@@rules_go++go_sdk+go_toolchains//:_0000_cel-spec__download_0_go_aix_ppc64'

```

This issue is similar to: https://github.com/bazel-contrib/rules_go/issues/4053

Reproduce the loongarch64 build and inspect the generated external rules_go+/go/toolchain/BUILD.bazel and rules_go++go_sdk+go_toolchains/BUILD.bazel locations shown in the error. Compare the missing loongarch64 target with the related rules_go issue 4053. Done means the build no longer reports the undeclared target on loongarch64.

Written by the indexing model from the issue text.