doc/ffserver: remove paragraph in the introductory blurb

The paragraph is about what ffserver is not and where to look for other
information, but is pretty redundant and distracting, especially
considering the new organization of the documentation.

doc/ffserver.texi

@@ -22,11 +22,6 @@ live feeds (you can seek to positions in the past on each live feed,
 provided you specify a big enough feed storage in
 @file{ffserver.conf}).
 
-This documentation covers only the streaming aspects of ffserver /
-ffmpeg. All questions about parameters for ffmpeg, codec questions,
-etc. are not covered here. Read @file{ffmpeg.html} for more
-information.
-
 @command{ffserver} receives prerecorded files or FFM streams from some
 @command{ffmpeg} instance as input, then streams them over
 RTP/RTSP/HTTP.