Fix for Vim 8.1.0648

[thinca]

From Vim 8.1.0648, the return value of operator-pending mode of mode(1) contains forced visual mode character at tail.

For example:

function! Cmd()
    let g:mode = mode(1)
    return ''
endfunction
onoremap <expr> i- Cmd()

normal di-
echo g:mode
" => 'no'

normal dvi-
echo g:mode
" => 'nov'

normal dVi-
echo g:mode
" => 'noV'

execute "normal d\<C-v>i-"
echo g:mode
" => "no\<C-v>"

The above change breaks this plugin.

This PR wraps mode() function to keep old behavior.

[rhysd]

Thank you! I did not know this and I did not notice it since I'm using slightly older Vim.