Stores.rst: update doc

Documentation/Store.rst

@@ -257,8 +257,8 @@ Store: *VARS* - V
 +=========================+============================================================================================================================================+
 | random                  | Random string with length of 32 alphanum chars (lower & upper case). This variable is always filled. Each access gives a new value.        |
 +-------------------------+--------------------------------------------------------------------------------------------------------------------------------------------+
-| randomUniq              | Like {{random:V}} but it's guaranteed that it's uniq. Optional: as *default* define an expiration time.                                    |
-|                         | Example: ``{{randomUniq:V}}``, ``{{randomUniq:V:::2020-12-15}}``, ``{{randomUniq:V:::+ 10 sec}}`` (Relative: sec, min, day).               |
+| randomUniq              | Like {{random:V}} but it's guaranteed that it's uniq. Optional: as *default* define an expiration time. Example: ``{{randomUniq:V}}``,     |
+|                         |  ``{{randomUniq:V:::2020-12-15}}``, ``{{randomUniq:V:::+ 10 sec}}`` (sec, min, day, ... - MySQL notation DATE_ADD() ).                     |
 +-------------------------+--------------------------------------------------------------------------------------------------------------------------------------------+
 | slaveId                 | see :ref:`slave-id`                                                                                                                        |
 +-------------------------+--------------------------------------------------------------------------------------------------------------------------------------------+