Migrate onSetMessage to onChatMessage

These were probably just missed. They cause warnings in the console and
make it so the Wintertodt plugin doesn't start

runelite-client/src/test/java/net/runelite/client/plugins/chatnotifications/ChatNotificationsPluginTest.java

@@ -76,7 +76,7 @@ public class ChatNotificationsPluginTest
 	}
 
 	@Test
-	public void onSetMessage()
+	public void onChatMessage()
 	{
 		when(config.highlightWordsString()).thenReturn("Deathbeam, Deathbeam OSRS , test");