SPIGOT-2540: Add nullability annotations to entire Bukkit API

By: Darkyenus <darkyenus@gmail.com>

paper-api/src/main/java/org/bukkit/entity/AnimalTamer.java

@@ -1,5 +1,8 @@
 package org.bukkit.entity;
 
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
 import java.util.UUID;
 
 public interface AnimalTamer {
@@ -9,6 +12,7 @@ public interface AnimalTamer {
      *
      * @return The name to reference on tamed animals or null if a name cannot be obtained
      */
+    @Nullable
     public String getName();
 
     /**
@@ -16,5 +20,6 @@ public interface AnimalTamer {
      *
      * @return The UUID to reference on tamed animals
      */
+    @NotNull
     public UUID getUniqueId();
 }