Fix documentation for PRESENCE_STATE to properly illustrate how to create a presence hint.

There was a missing comma.
This was discovered by Dan Kaplan.
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Merged revisions 409886 from http://svn.asterisk.org/svn/asterisk/branches/11
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Merged revisions 409887 from http://svn.asterisk.org/svn/asterisk/branches/12


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@409888 65c4cc65-6c06-0410-ace0-fbb531ad65f3