Add Override annotations where appropriate

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

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

@@ -31,6 +31,7 @@ public class Button extends SimpleAttachableMaterialData implements Redstone {
      *
      * @return true if powered, otherwise false
      */
+    @Override
     public boolean isPowered() {
         return (getData() & 0x8) == 0x8;
     }
@@ -50,6 +51,7 @@ public class Button extends SimpleAttachableMaterialData implements Redstone {
      *
      * @return BlockFace attached to
      */
+    @Override
     public BlockFace getAttachedFace() {
         byte data = (byte) (getData() & 0x7);
 
@@ -79,6 +81,7 @@ public class Button extends SimpleAttachableMaterialData implements Redstone {
     /**
      * Sets the direction this button is pointing toward
      */
+    @Override
     public void setFacingDirection(BlockFace face) {
         byte data = (byte) (getData() & 0x8);