Print post-processing error in multi-line paragraph

Related #510

plug.vim

@@ -1044,14 +1044,14 @@ function! s:update_finish()
         call s:log4(name, 'Updating submodules. This may take a while.')
         let out .= s:bang('git submodule update --init --recursive 2>&1', spec.dir)
       endif
-      let msg = printf('%s %s: %s', v:shell_error ? 'x': '-', name, s:lastline(out))
+      let msg = s:format_message(v:shell_error ? 'x': '-', name, out)
       if v:shell_error
         call add(s:update.errors, name)
         call s:regress_bar()
         silent execute pos 'd _'
         call append(4, msg) | 4
       elseif !empty(out)
-        call setline(pos, msg)
+        call setline(pos, msg[0])
       endif
       redraw
     endfor