[llvm-rc] Allow -1 for menu item IDs

This seems to be used in some resource files, e.g.
https://github.com/wxWidgets/wxWidgets/blob/f3217573d7240411e7817c9d76d965b2452987a2/include/wx/msw/wx.rc#L28.

MSVC rc.exe and GNU windres both allow any value here, and silently
just truncate to uint16_t range. This just explicitly allows the
-1 value and errors out on others - the same was done for control
IDs in dialogs in c1a67857.

Differential Revision: https://reviews.llvm.org/D76951