[vim] Display relative path in prompt

plugin/fzf.vim

@@ -588,7 +588,7 @@ function! s:cmd(bang, ...) abort
     let opts.dir = substitute(substitute(remove(args, -1), '\\\(["'']\)', '\1', 'g'), '/*$', '/', '')
     let opts.options .= ' --prompt '.shellescape(opts.dir)
   else
-    let opts.options .= ' --prompt '.shellescape(pathshorten(getcwd()).'/')
+    let opts.options .= ' --prompt '.shellescape(pathshorten(fnamemodify(getcwd(), ':~:.')).'/')
   endif
   let opts.options .= ' '.join(args)
   call fzf#run(fzf#wrap('FZF', opts, a:bang))