Apply typehints to pocketmine\network\mcpe\protocol namespace

this is pulled from network-nuke in order to reduce the size of the diff.

src/pocketmine/network/mcpe/protocol/SpawnExperienceOrbPacket.php

@@ -37,12 +37,12 @@ class SpawnExperienceOrbPacket extends DataPacket{
 	/** @var int */
 	public $amount;
 
-	protected function decodePayload(){
+	protected function decodePayload() : void{
 		$this->position = $this->getVector3();
 		$this->amount = $this->getVarInt();
 	}
 
-	protected function encodePayload(){
+	protected function encodePayload() : void{
 		$this->putVector3($this->position);
 		$this->putVarInt($this->amount);
 	}