Add Override annotations where appropriate

By: md_5 <git@md-5.net>

paper-api/src/main/java/org/bukkit/material/PistonExtensionMaterial.java

@@ -22,6 +22,7 @@ public class PistonExtensionMaterial extends MaterialData implements Attachable
         super(type, data);
     }
 
+    @Override
     public void setFacingDirection(BlockFace face) {
         byte data = (byte) (getData() & 0x8);
 
@@ -45,6 +46,7 @@ public class PistonExtensionMaterial extends MaterialData implements Attachable
         setData(data);
     }
 
+    @Override
     public BlockFace getFacing() {
         byte dir = (byte) (getData() & 7);
 
@@ -84,6 +86,7 @@ public class PistonExtensionMaterial extends MaterialData implements Attachable
         setData((byte) (sticky ? (getData() | 0x8) : (getData() & ~0x8)));
     }
 
+    @Override
     public BlockFace getAttachedFace() {
         return getFacing().getOppositeFace();
     }