paren was misplaced.  The error apparently appeared when resetting the
doc to XML or DocBook.  Note that lspmap.png was erroneously updated
to reflect the typo in r8547 and so it's been wrong since then too.
The original HTML spec was correct (as is the code).

Also remove the associated rendered versions of the typeset equations
as they're no longer used (and lspmap.png was incorrect as described
above anyway)
 

svn path=/trunk/vorbis/; revision=19450