doc: Add macros and typedefs to the documentation

If somebody bothered to put a doxygen comment in for a macro or
typedef, make it appear in the pages. This produces documentation
for wl_container_of and wl_dispatcher_func_t from the _8h files.

Reviewed-by: "Jon A. Cruz" <jonc@osg.samsung.com>
Reviewed-by: Bryce Harrington <bryce@osg.samsung.com>