This also does not change th code. It is an advertisement to a linter-loke tool to take some action on the source code. Its most similar to linter directives which usually are comments.

We're talking about the "//go" comments in general I think here.

Things like "//go:embed" and "//go:build" very much do change the semantics of source code.

The comments above 'import "C"' containing C function definitions and imports change the compilation of go source code.

The "//go" comments contain a mix of ones that must be respected to compile, to being optional, to being entirely ignorable (like generate and fix).