添加隐藏模式marathon_bfmax的入口并修改tip关于隐藏模式的说法

parts/language/lang_en.lua

@@ -892,7 +892,7 @@ return{
 		"Techmino is so fun!",
 		"TetroDictionary is now available in English.",
 		"The stacker future is yours in Techmino!",
-		"There are three hidden modes in the game.",
+		"There are four hidden modes in the game.",
 		"There is a total of 18 different pentominoes.",
 		"There is a total of 7 different tetrominoes.",
 		"Try using multiple Hold Queues!",
@@ -931,4 +931,4 @@ return{
 		{C.Y,"O-Spin Triple!"},
 		{C.Z,"What? ",C.lC,"Xspin?"},
 	}
-}
+}