すべてのタブをスペースに書き換えたくする設定

vim 
function AddUnderLineToInvisibleCharacters()
    syntax match MultiByte /　/     display containedin=ALL
    syntax match SpaceLine /^\s\+$/ display containedin=ALL
    syntax match TabSpace  /\t/     display containedin=ALL
    highlight def MultiByte cterm=underline ctermfg=Blue  guifg=Blue
    highlight def SpaceLine cterm=underline ctermfg=Green guifg=Green
    highlight def TabSpace  cterm=underline ctermfg=Red   guifg=Red
endf
au BufRead,BufNew * call AddUnderLineToInvisibleCharacters()