add vim filetype check::
.vimrc +
filetype on "filetype enable. this is call $VIMRUNTIME/filetype.vim script of file name -> file type .but this don't.call $VIMRUNTIME/srcript.vim from file content check file type.
filetype plugin on "this is call $VIMRUNTIME/ftplugin.vim
filetype indent on "file type auto indent.