Turn off Doxygen warnings for undocumented API, for now.
Turn off Doxygen warnings for undocumented API, for now.

But warn about absent parameter documentation for functions that are
otherwise documented.

topcat/xcb-win32,stapelberg/libxcb,topcat/xcb-win32,stapelberg/libxcb,topcat/xcb-win32,OpenInkpot-archive/iplinux-libxcb,OpenInkpot-archive/iplinux-libxcb,topcat/xcb-win32,topcat/xcb-win32,stapelberg/libxcb,OpenInkpot-archive/iplinux-libxcb