when play button is focused on title screen and either attack or jump button is pressed, start level

fcore/title/title-update.sml

@@ -2,5 +2,16 @@ structure TitleUpdate =
 struct
   open TitleType
 
-  fun update (titleState, input) = titleState
+  fun update (titleState, input: FrameInputType.t, userKeys) =
+    case #focus titleState of
+      START_BUTTON =>
+        let
+          val mode =
+            if #attackHeld input orelse #jumpHeld input then
+              GameType.LEVEL LevelType.initial
+            else
+              GameType.TITLE titleState
+        in
+          {mode = mode, userKeys = userKeys}
+        end
 end