docs: fixup manpage syntax for rtapi_app_main.3 & rtapi_app_exit.3

Before this, the rtapi_app_main.3 manpage had the #include and the
function declaration on the same line, this breaks them apart to separate
lines.

Also adds the #include <rtapi.h> to th rtapi_app_exit.3 manpage.

Signed-off-by: Sebastian Kuzminsky <seb@highlab.com>
docs: improve 'option rtapi_app no' description of comp/halcompile

Signed-off-by: Sebastian Kuzminsky <seb@highlab.com>
docs -reworked some stuff on gmoccapy.txt

Signed-off-by: Norbert Schechner <nieson@web.de>