Add methods to get translation keys

Co-authored-by: MeFisto94 <MeFisto94@users.noreply.github.com>

paper-api/src/main/java/org/bukkit/Translatable.java

@@ -5,14 +5,18 @@ import org.jetbrains.annotations.NotNull;
 /**
  * Represents an object with a text representation that can be translated by the
  * Minecraft client.
+ * @deprecated use {@link net.kyori.adventure.translation.Translatable}
  */
+@Deprecated(forRemoval = true) // Paper
 public interface Translatable {
 
     /**
      * Get the translation key, suitable for use in a translation component.
      *
      * @return the translation key
+     * @deprecated look for a {@code translationKey()} method instead
      */
     @NotNull
+    @Deprecated(forRemoval = true) // Paper
     String getTranslationKey();
 }