Adding/expanding documentation

By: Celtic Minstrel <celtic.minstrel.ca@some.place>

paper-api/src/main/java/org/bukkit/block/PistonMoveReaction.java

@@ -4,8 +4,17 @@ import java.util.HashMap;
 import java.util.Map;
 
 public enum PistonMoveReaction {
+    /**
+     * Indicates that the block can be pushed or pulled.
+     */
     MOVE(0),
+    /**
+     * Indicates the block is fragile and will break if pushed on.
+     */
     BREAK(1),
+    /**
+     * Indicates that the block will resist being pushed or pulled.
+     */
     BLOCK(2);
 
     private int id;
@@ -20,10 +29,17 @@ public enum PistonMoveReaction {
         this.id = id;
     }
 
+    /**
+     * @return The ID of the move reaction
+     */
     public int getId() {
         return this.id;
     }
 
+    /**
+     * @param id An ID
+     * @return The move reaction with that ID
+     */
     public static PistonMoveReaction getById(int id) {
         return byId.get(id);
     }