Tweak some Doxygen markup and comments.
Tweak some Doxygen markup and comments.

* subversion/include/svn_client.h
  (svn_client_checkout2): Mark errors up with @c.
  (svn_client_blame): Correct name of function that replaced this one.

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