audio: error hints need a trailing \n

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
diff --git a/audio/audio.c b/audio/audio.c
index 730bf24..9862157 100644
--- a/audio/audio.c
+++ b/audio/audio.c
@@ -1833,7 +1833,7 @@
             card->state = audio_init(NULL, errp);
             if (!card->state) {
                 if (!QSIMPLEQ_EMPTY(&audiodevs)) {
-                    error_append_hint(errp, "Perhaps you wanted to set audiodev=%s?",
+                    error_append_hint(errp, "Perhaps you wanted to set audiodev=%s?\n",
                                       QSIMPLEQ_FIRST(&audiodevs)->dev->id);
                 }
                 return false;