Better support for varargs in functions in classes declared with @field

I ran into a minor problem with how vararg is handled in function declarations in an field annotation when the function declaration itself later explicitly lists the arguments.

---@class Handler
---@field ReceiveMsg fun(self: Handler, type: number, ...: string)
local handler = {}

function handler:ReceiveMsg(arg1, arg2, arg3, arg4)
 --- arg2 is inferred as string, but arg3 and arg4 are "any"
end

Why do I even have this mismatch between field and function declaration? The field annotation comes from a library and is an event handler -- the number of parameters depend on a lot of things, but for a given implementation you usually only care about a few that you explicitly declare.

Commencez par reproduire l’exemple de Handler de l’issue avec une annotation vararg @field ReceiveMsg et une déclaration explicite de méthode. Suivez la propagation du type vararg pendant la déclaration de fonction et l’inférence des paramètres. C’est terminé lorsque arg2, arg3 et arg4 sont systématiquement inférés comme string, au lieu de laisser les arguments suivants comme any.