libavformat/movenc: mov: added subtitle codec tags to codec tag list

This fixes avformat_query_codec incorrectly returning 0 for
mov container and mov_text subtitles.
Signed-off-by: Paweł Wegner <pawel.wegner95@gmail.com>
Signed-off-by: James Almer <jamrial@gmail.com>

libavformat/movenc.c

@@ -6858,7 +6858,7 @@ AVOutputFormat ff_mov_muxer = {
     .deinit            = mov_free,
     .flags             = AVFMT_GLOBALHEADER | AVFMT_ALLOW_FLUSH | AVFMT_TS_NEGATIVE,
     .codec_tag         = (const AVCodecTag* const []){
-        ff_codec_movvideo_tags, ff_codec_movaudio_tags, 0
+        ff_codec_movvideo_tags, ff_codec_movaudio_tags, ff_codec_movsubtitle_tags, 0
     },
     .check_bitstream   = mov_check_bitstream,
     .priv_class        = &mov_muxer_class,