fix documentation typo. thanks to David K. Gasaway.

svn path=/trunk/vorbis/; revision=3963

doc/vorbis-ogg.html

@@ -84,9 +84,9 @@ zero.<p>
 
 <li>Vorbis packets may span page boundaries. <p>
 
-<li>The granule position of pages contining Vorbis audio is in units
+<li>The granule position of pages containing Vorbis audio is in units
 of PCM audio samples (per channel; a stereo stream's granule position
-does no increment at twice the speed of a mono stream).<p>
+does not increment at twice the speed of a mono stream).<p>
 
 <li>The granule position of a page represents the end PCM sample
 position of the last packet <em>completed</em> on that page.  A page