The code generator will use the package name, along with the determined Go module name, to
decide where to place the corresponding Go files.
If the package is not a member of the determined Go module name, it is omitted from codegen,
and it is assumed that the Go package is published somewhere else.
Example:
@go.Package { name = "github.com/myteam/myproj/appconfig" }
module myteam.myproj.AppConfig
import package://pkg.pkl-lang.org/pkl-go/pkl.golang@<VERSION>#/go.pkl"
Metadata for the corresponding Go package for the annotated Pkl module.