Properly handling of enum imports

[wjiec]

1. properly importing enums from multiple packages/namespaces with the same name(in/not in rules)
2. reduce unnecessary duplication of import and alias

For example, a proto with this message

...
import "foo/v1/datatype.proto"
import "bar/v1/datatype.proto"
...

message CreateSomethingRequest {
  foo.v1.Foo.FooType foo_type = 1 [(validate.rules).enum = {in: [1, 2, 3, 4]}];
  bar.v1.Bar.BarType bar_type = 2 [(validate.rules).enum = {not_in: [1, 2, 3, 4]}];
}

and run go vet ./... in generated code

# example.com/buf-pgv/zoo/api/v1
vet: zoo/api/v1/zoo.pb.validate.go:187:46: undeclared name: v1

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[rodaine]

Thanks for the patch, @wjiec! Can you add a test case to the harness so that we can ensure this doesn't regress?

[wjiec]

Thanks for the patch, @wjiec! Can you add a test case to the harness so that we can ensure this doesn't regress?

Okay, I'll add some test cases later in the week.

[wjiec]

Hi @rodaine, I've added some test cases to the PR

[rodaine]

Thanks so much for the patch!