nogo not getting run with customized go rule

### What version of rules_go are you using?
rules_go-v0.25.1

### What version of gazelle are you using?
v0.22.3

### What version of Bazel are you using?
4.1.0-bd3243f705b1d9afb853a7d94d17992f8a055261

### Does this issue reproduce with the latest releases of all the above?
Yes

### What operating system and processor architecture are you using?
Ubuntu Focal (U20), x86_64

### Any other potentially useful information about your toolchain?

### What did you do?
I'm not using rules_go defined go targets. ie. `load("@io_bazel_rules_go//go:def.bzl", "go_library", "go_binary")`
If I'm using a custom defined go rule, is there a way to have nogo run when the target is built?
In addition, can I build nogo as a target and run it as a binary?

### What did you expect to see?

### What did you see instead?

Start with the custom rule scenario and the rules_go go:def.bzl entry points named in the issue, especially go_library and go_binary. Trace how nogo is connected to those targets, then investigate whether it can be built and run independently. Done means a reproducible answer covering both custom-rule integration and standalone nogo execution.

Written by the indexing model from the issue text.