hide dead NPCs for EntityHider (#1197)

runelite-api/src/main/java/net/runelite/api/Client.java

@@ -1478,6 +1478,13 @@ public interface Client extends GameShell
 	 */
 	void setProjectilesHidden(boolean state);
 
+	/**
+	 * Sets whether dead NPCs are hidden.
+	 *
+	 * @param state new NPC hidden state
+	 */
+	void setDeadNPCsHidden(boolean state);
+
 	/**
 	 * Gets an array of tile collision data.
 	 * <p>