Update WC API docs about the reporting of externals, following the change from collecting "traversal info" to calling an "svn_wc_external_update_t" callback function that was made in r879231.
Update WC API docs about the reporting of externals, following the change
from collecting "traversal info" to calling an "svn_wc_external_update_t"
callback function that was made in r879231.

* subversion/include/svn_wc.h
  (svn_wc_external_update_t): Document the parameters of this callback.
  (svn_wc_get_status_editor5, svn_wc_crawl_revisions5): Update the doc
    string to describe the use of the new callback.


git-svn-id: f8a4e5e023278da1e04e203c7fe051e3c4285d88@1082118 13f79535-47bb-0310-9956-ffa450edef68

YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,wbond/subversion,YueLinHo/Subversion,wbond/subversion,YueLinHo/Subversion,wbond/subversion,YueLinHo/Subversion,YueLinHo/Subversion,wbond/subversion,wbond/subversion,wbond/subversion,wbond/subversion,YueLinHo/Subversion