When format provide doesn't exist, use removing trailing white spaces as a fallback

[Freed-Wu]

I want to share a method: when the format provide doesn't exist, we can use removing trailing whitespace as a fallback.

function! init#coc#format(isvisual) abort
  if a:isvisual
    if CocHasProvider('format')
      call CocActionAsync('formatSelected', visualmode())
    else
      *TrailGuide fix
    endif
  else
    if CocHasProvider('format')
      call CocActionAsync('format')
    else
      TrailGuide fix
    endif
  endif
endfunction

xnoremap <silent> gq :<C-U>call init#coc#format(v:true)<CR>
nnoremap <silent> gqq :<C-U>call init#coc#format(v:false)<CR>

The TrailGuide is a vim plugin to removing trailing whitespaces.

Inspired by #4831 (comment).