Introduced new implicit variable named newState (openhab#1029)

Signed-off-by: Laurent Garnier <[email protected]>

configuration/rules-dsl.md

@@ -684,6 +684,7 @@ Besides the implicitly available variables for items and commands/states, rules
 
 - `receivedCommand` - will be implicitly available in every rule that has at least one command event trigger.
 - `previousState` - will be implicitly available in every rule that has at least one status change event trigger.
+- `newState` - will be implicitly available in every rule that has at least one status update or status change event trigger.
 - `triggeringItem` - will be implicitly available in every rule that has at least one command, status update, or status change event trigger.
 - `receivedEvent` - will be implicitly available in every rule that has a channel-based trigger.