fix: use correct Rust variant name for enum aliases

[jstarks]

This change fixes code generation of protobuf enums when aliases are present.

[tustvold]

Closed by #103

[jstarks]

Won't #103 just ignore the aliases in deserialize? This seems incomplete and will lead to deserialization failures.

[tustvold]

You can define aliases by assigning the same value to different enum constants. To do this you need to set the allow_alias option to true, otherwise the protocol compiler generates a warning message when aliases are found. Though all alias values are valid during deserialization, the first value is always used when serializing.

That is a valid point, I would be happy to review a PR to address this aspect and add a corresponding test for it

[jstarks]

This PR addressed addressed that aspect, but it didn't add an explicit test.

Unfortunately, I am having trouble getting the CLA signed, so it might be better to reimplement this (small) change.

[sporkmonger]

I can take a look at this gap in a bit since I don't have any limitations with respect to the CLA.