Ogg Opus wording - avoid repeated 'this' in the abstract.

doc/draft-terriberry-oggopus.xml

@@ -46,10 +46,10 @@ This document defines the Ogg encapsulation for the Opus interactive speech and
  audio codec.
 This allows data encoded in the Opus format to be stored in an Ogg logical
  bitstream.
-This provides Opus with a long-term storage format supporting all of the
- essential features, including metadata, fast and accurate seeking, corruption
- detection, recapture after errors, low overhead, and the ability to multiplex
- Opus with other codecs (including video) with minimal buffering.
+Ogg encapsulation provides Opus with a long-term storage format supporting
+ all of the essential features, including metadata, fast and accurate seeking,
+ corruption detection, recapture after errors, low overhead, and the ability to
+ multiplex Opus with other codecs (including video) with minimal buffering.
 It also provides a live streamable format, capable of delivery over a reliable
  stream-oriented transport, without requiring all the data, or even the total
  length of the data, up-front, in a form that is identical to the on-disk