Tweak doxygen markup.
Tweak doxygen markup.

* subversion/include/svn_client.h
  (svn_client_add3, svn_client_import2, svn_client_blame3,
   svn_client_blame2, svn_client_export3, svn_client_lock): Markup
   boolean values with @c.

Patch by: Madan U Sreenivasan <madan@collab.net>

jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion