[Scarpet] Added ability to cancel events (#1497)

* Added ability to cancel events

* Made more events cancellable

* Added event_priority to __config

* Check for string values for performance

* Made player_finishes_using_item cancellable

* Made player_chooses_recipe cancellable

* Made player_swaps_hands cancellable

* Made player_message cancellable

* Added __on_player_placing_block (#1498)

* Added event to docs, keywords, event_test

* Added docs for event cancellation

docs/scarpet/resources/editors/npp/scarpet.xml

@@ -120,6 +120,7 @@
                 __on_player_interacts_with_entity(player, entity, hand) ->
                 __on_player_jumps(player) ->
                 __on_player_picks_up_item(player, item) ->
+                __on_player_placing_block(player, item_tuple, hand, block) ->
                 __on_player_places_block(player, item_tuple, hand, block) ->
                 __on_player_releases_item(player, item_tuple, hand) ->
                 __on_player_rides(player, forward, strafe, jumping, sneaking) ->