Document .gitignore split
Document .gitignore split

This is taken verbatim from the linux kernel .gitignore

Signed-off-by: Eduardo Lima (Etrunko) <bf50f4f8e28a384aa002f367e1f3608d165ff6d4@intel.com>

tasn/elementary,tasn/elementary,tasn/elementary,rvandegrift/elementary,FlorentRevest/Elementary,FlorentRevest/Elementary,rvandegrift/elementary,tasn/elementary,rvandegrift/elementary,tasn/elementary,FlorentRevest/Elementary,rvandegrift/elementary,FlorentRevest/Elementary