Fix :Maps when :verbose map does not have a 2nd line with comments (#1067)

autoload/fzf/vim.vim

@@ -1234,6 +1234,9 @@ function! fzf#vim#maps(mode, ...)
       call add(list, printf('%s %s', curr, s:green(src, 'Comment')))
       let curr = ''
     else
+      if !empty(curr)
+        call add(list, curr)
+      endif
       let curr = line[3:]
     endif
   endfor