Tag the nogo alias manual like the target behind it (#4759)

**What type of PR is this?**

Bug fix

**What does this PR do? Why is it needed?**

The `nogo` macro tags `<name>_actual` `manual`, so wildcards like
`//...` skip it; the comment in the macro explains why. The alias
`<name>`, which selects between that target and `//:default_nogo`, gets
no tags, so `bazel build //...` and `bazel test //...` match the alias
and build nogo anyway.

That build happens in a configuration derived from the target
configuration (via `go_tool_transition`), not the exec configuration in
which every Go target builds nogo. It is therefore a complete second
build of nogo and all its analyzers' dependencies that nothing consumes.
In our repository that was about 500 `GoCompilePkg` actions.

This passes the same tags to the alias. nogo is still built as a tool
dependency of every Go target, as before.

**Which issues(s) does this PR fix?**

None filed.

**Other notes for review**

`tests/core/nogo/wildcard` checks that both targets the macro creates
are tagged `manual`. Without the change it fails with `//:my_nogo is not
tagged manual; manual targets: [//:my_nogo_actual]`.

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Co-authored-by: Claude Opus 5.5 (1M context) <noreply@anthropic.com>