Prepend '::' to Twirp::Service and Twirp::Client to prevent namespace collisions

[etipton]

I ran into this issue when I structured my protobufs in such a way that the resulting ruby file ended up like...

module CompanyName
  module Twirp
    class MyNewService < Twirp::Service
[...]

which causes:

uninitialized constant CompanyName::Twirp::Service (NameError)

---

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[etipton]

workaround, for anyone who stumbles on this:

module CompanyName
  module Twirp
    Service = ::Twirp::Service
    Client  = ::Twirp::Client
  end
end

[wmatveyenko]

Hi. Thanks for your contribution. Can you add some tests that catch this error? Also, please add a comment with "By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license."

[etipton]

Hi. Thanks for your contribution. Can you add some tests that catch this error? Also, please add a comment with "By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license."

Updated the PR description w/ that comment.

Hmm, would that be a go test since it's testing the code-generation? (TBH my golang-fu is not very strong 😬)

But -- this change is so simple that as long as existing tests still pass, it should be acceptable IMO. Here is all that prefixing with :: means, if unfamiliar: https://stackoverflow.com/a/10064341/1938879 -- but if you still feel a spec is necessary, could you help write one / refer someone to help?

[etipton]

(Also thx for taking a look!)

[wmatveyenko]

Thanks for the explanation.