cosmetics: Align muxer/demuxer declarations

Also add missing trailing commas, break long codec_tag lines and
add spaces in codec_tag declarations.

Signed-off-by: Martin Storsjö <martin@martin.st>

libavformat/cdg.c

@@ -68,5 +68,5 @@ AVInputFormat ff_cdg_demuxer = {
     .long_name      = NULL_IF_CONFIG_SMALL("CD Graphics Format"),
     .read_header    = read_header,
     .read_packet    = read_packet,
-    .extensions = "cdg"
+    .extensions     = "cdg",
 };