doc/muxers: remove "-strict experimental" from tee muxer examples

Examples use the native FFmpeg AAC encoder but it is no longer
considered experimental and therefore not required.
Signed-off-by: Lou Logan <lou@lrcd.com>

doc/muxers.texi

@@ -1661,7 +1661,7 @@ keyframes packets, as requested by the MPEG-TS format. The select
 option is applied to @file{out.aac} in order to make it contain only
 audio packets.
 @example
-ffmpeg -i ... -map 0 -flags +global_header -c:v libx264 -c:a aac -strict experimental
+ffmpeg -i ... -map 0 -flags +global_header -c:v libx264 -c:a aac
        -f tee "[bsfs/v=dump_extra]out.ts|[movflags=+faststart]out.mp4|[select=a]out.aac"
 @end example
 
@@ -1670,7 +1670,7 @@ As below, but select only stream @code{a:1} for the audio output. Note
 that a second level escaping must be performed, as ":" is a special
 character used to separate options.
 @example
-ffmpeg -i ... -map 0 -flags +global_header -c:v libx264 -c:a aac -strict experimental
+ffmpeg -i ... -map 0 -flags +global_header -c:v libx264 -c:a aac
        -f tee "[bsfs/v=dump_extra]out.ts|[movflags=+faststart]out.mp4|[select=\'a:1\']out.aac"
 @end example
 @end itemize