Update comment about URIs in relpath function.
Update comment about URIs in relpath function.

Found by: stsp

* subversion/libsvn_subr/dirent_uri.c
  (svn_relpath_is_canonical): Update comment.

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