On the 'move-tracking-2' branch: improve doc strings and parameter names.

* subversion/include/private/svn_editor3.h
  (svn_editor3_put,
   svn_editor3__shim_fetch_func_t,
   svn_delta__ev3_from_delta_for_commit,
   svn_delta__delta_from_ev3_for_commit,
   svn_editor3__insert_shims):
    Improve documentation. Rename params.

* subversion/libsvn_delta/compat3.c
  (ev3_edit_baton,
   map_to_repos_relpath,
   svn_delta__delta_from_ev3_for_commit): Rename params.

* subversion/libsvn_ra/ra_loader.c
  (fetch): Rename params.

* subversion/libsvn_repos/commit.c
  (fetch_func): Rename params.

git-svn-id: https://svn.apache.org/repos/asf/subversion/branches/move-tracking-2@1623960 13f79535-47bb-0310-9956-ffa450edef68