Document the obsolete '-N' option more precisely in 'svn help'.
It previously said "try --depth=files or --depth=immediates" but for each command it means some specific depth, and not always one of those two.
* subversion/svn/svn.c (svn_cl__options): Remove not-very-helpful "try ..." message from the default description of '-N'. This description will no longer be used. (svn_cl__cmd_table): Add a specific message for '-N' for each command that accepts it.