Deprecate old EventContextKeys

Signed-off-by: Gabriel Harris-Rouquette <gabizou@me.com>

Author: gabizou

src/main/java/org/spongepowered/api/event/EventContextKeys.java

@@ -166,21 +166,25 @@ public final class EventContextKeys {
 
     /**
      * Used when leaves decay.
+     * @deprecated Use {@link BlockTransaction#operation()} instead.
      */
     public static final EventContextKey<ServerWorld> LEAVES_DECAY = EventContextKeys.key(ResourceKey.sponge("leaves_decay"), ServerWorld.class);
 
     /**
      * Used when flowing liquid causing another block to break.
+     * @deprecated Use {@link BlockTransaction#operation()} instead.
      */
     public static final EventContextKey<ServerWorld> LIQUID_BREAK = EventContextKeys.key(ResourceKey.sponge("liquid_break"), ServerWorld.class);
 
     /**
      * Used when flowing liquid moves to another location.
+     * @deprecated Use {@link BlockTransaction#operation()} instead.
      */
     public static final EventContextKey<ServerWorld> LIQUID_FLOW = EventContextKeys.key(ResourceKey.sponge("liquid_flow"), ServerWorld.class);
 
     /**
      * Used when liquid changes state.
+     * @deprecated Use {@link BlockTransaction#operation()} instead.
      */
     public static final EventContextKey<ServerWorld> LIQUID_MIX = EventContextKeys.key(ResourceKey.sponge("liquid_mix"), ServerWorld.class);