Type packs are not supported in declaration files

[Ukendio]

Right now there's a gap in the syntax for declaration files with the lack of support for generic type packs.

One way it can be resolved is using the preexisting construct of Parser::parseGenericTypeList to get a list of the type packs. However I was told that it may require some post processing of the returned lists as self doesn't need an annotation, but all other parameters needs to be annotated. Additionally I was told that TypeInfer.cpp and ConstraintGenerator.cpp may require changes to handle the varargs

[Ukendio]

Split between whether this should be a bug report or a feature request but I will let moderators handle that1