Fix perfect forwarding in TypedAllocator::allocate. (#2008)

The original wasn't actually allowing universal references and if you
have a datatype with a deleted copy constructor, the template
substitution would fail here. This lets me use `TypedAllocator` for some
type that isn't copyable. I doubt there would be any performance
difference due to copy elision anyway.

Author: alexmccord

Analysis/include/Luau/TypedAllocator.h

@@ -49,7 +49,7 @@ class TypedAllocator
 
         T* block = stuff.back();
         T* res = block + currentBlockSize;
-        new (res) T(std::forward<Args&&...>(args...));
+        new (res) T(std::forward<Args>(args)...);
         ++currentBlockSize;
         return res;
     }