Add to reserved keywords

[yucombinator]

It is no longer possible to declare types that overrides existing builtins since HHVM 4.28, so we need to add to the list of reserved keywords to avoid possible collisions.

https://hhvm.com/blog/2019/10/23/hhvm-4.28.html

Declaring a type with the same name as a built-in type (e.g. int, Vector, Awaitable) will no longer override the built-in type. Such types can now only be referenced using their namespaced name (e.g. MyNamespace\Vector, or namespace\Vector if in the same namespace).

https://hhvm.com/blog/2019/11/06/hhvm-4.30.html

it is no longer possible to override built-in types using use statements (use MyVector as Vector, use MyType as string, etc.)

This PR adds a list of reserved keywords (possibly might be missing some?). Also ran gofmt over plugin.go

A list of reserved words can be found at https://github.com/facebook/hhvm/blob/master/hphp/hack/src/naming/naming_special_names.rs

[renaudb]

I think either the words in this list should be lowercased or they should be lowercased before comparison here:

proto-hack/protoc-gen-hack/plugin.go

Line 246 in 952fe37

for _, keyword := range reservedKeywords {

[yucombinator]

good catch, I've updated the PR but lowercasing keywords on line 246

[y3llowcake]

Can you describe the motivation for this change in a bit more detail? Did you run into a specific name-collision, if so, which one?

A number of the elements you are adding are not "language keywords" they are names from [namespaced] library code. For example, if I create a protobuf with a package named "foobar" a message named "Iterable", does anything actually break?