mention the two asf formats

Originally committed as revision 2067 to svn://svn.ffmpeg.org/ffmpeg/trunk

doc/ffserver.conf

@@ -79,7 +79,8 @@ Feed feed1.ffm
 # ra         : Real Networks compatible stream. Audio only.
 # mpjpeg     : Multipart JPEG (works with Netscape without any plugin)
 # jpeg       : Generate a single JPEG image.
-# asf        : ASF compatible stream (Windows Media Player format).
+# asf_stream : ASF compatible streaming (Windows Media Player format).
+# asf        : ASF file (not streamed)
 # swf        : Macromedia flash(tm) compatible stream
 # avi        : AVI format (open divx video, mpeg audio sound)
 # master     : special ffmpeg stream used to duplicate a server