Removes extra qualification in function signature

[Biswa96]

This fixes the following compiler error with gcc.

laf/os/win/dnd.h:59:15: error: extra qualification
'os::DragTargetAdapter::' on member 'newDragEven' [-fpermissive]
59 | DragEvent DragTargetAdapter::newDragEvent(POINTL* pt, DWORD* pdwEffect);
   |           ^~~~~~~~~~~~~~~~~

[dacap]

Thanks for this @Biswa96, I just found this when doing a full clang-format in: f6bf172 (fixed on beta), I should cherry pick that commit onto main too.