Added documentation for YCM extenstion
Added documentation for YCM extenstion

Signed-off-by: Evgeny Firsov <0bbd1785cc6f5766d8c1540da97a7d9baef7f90e@gmail.com>

mildred/vim-airline,blueyed/vim-airline,wilywampa/vim-airline,tschundler/dotfiles,HarmtH/vim-airline,bling/vim-airline,dalguji/vim-airline,tschundler/dotfiles,unphased/vim-airline,tschundler/dotfiles,sappo/vim-airline,rchicoli/vim-airline,chrisbra/vim-airline,vim-IDE/vim-airline,yzhou61/vim-airline