Remove an unnecessary comma.

doc/draft-ietf-codec-oggopus.xml

@@ -1151,7 +1151,7 @@ To achieve good quality in the very first samples of a stream, the Ogg encoder
  MAY use LPC extrapolation to generate at least 120 extra samples
  (extra_samples) at the beginning to avoid the Opus encoder having to encode
  a discontinuous signal.
-For an input file containing length samples, the Ogg encoder, SHOULD set the
+For an input file containing length samples, the Ogg encoder SHOULD set the
  preskip header flag to samples_delay+extra_samples, encode at least
  length+samples_delay+extra_samples samples, and set the granulepos of the last
  page to length+samples_delay+extra_samples.