Remove already completed step from 06.heads_up_display.rst

This was done at the end of the previous page, i.e., in https://docs.godotengine.org/en/stable/getting_started/first_2d_game/05.the_main_game_scene.html#testing-the-scene

(Replaces #9676 )

Author: codingthat

getting_started/first_2d_game/06.heads_up_display.rst

@@ -273,8 +273,7 @@ with the changing score:
     ``_ready()`` if you haven't already, otherwise
     your game will start automatically.
 
-Now you're ready to play! Click the "Play the Project" button. You will be asked
-to select a main scene, so choose ``main.tscn``.
+Now you're ready to play! Click the "Play the Project" button.
 
 Removing old creeps
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