Fixes some minor issues

Adds some missing save arena method calls for parkourArena's edit methods.
Adds a message when a player reaches a new parkour checkpoint, and makes sure to avoid repeated messages.
Adds /dleave and /pleave as aliases to /minigamesleave

src/main/resources/plugin.yml

@@ -17,6 +17,8 @@ commands:
   miniGamesLeave:
     aliases:
       - mleave
+      - dleave
+      - pleave
     permission: minigames.join
     usage: /<command>
     description: Used to leave the current dropper arena