Document old enderpearl behaviour world config (#542)

Author: Doc94

config-specs/paper/paper-world-defaults.yml

@@ -892,6 +892,12 @@ misc:
       Determines if the server will interrupt a sprinting player if they are
       attacked. When set to true, you may be subject to a Vanilla bug where
       sprinting is stopped and started when attacking players.
+  legacy-ender-pearl-behavior:
+    default: "false"
+    description: >-
+      Determines if the server uses legacy (pre-1.21.2) ender pearl behavior.
+      If enabled, ender pearls will no longer load chunks and will be saved with
+      the launching player instead of being saved as independent entities in the world.
   light-queue-size:
     default: "20"
     description: >-