Update 05.the_main_game_scene.rst

[koubaa]

Make the 2d tutorial slightly more straightforward

Handle assigning the position before setting the direction

[tetrapod00]

In theory I agree, since the position is set between two lines of code about setting the direction.
Note that the demo project has a completed version, too, and if we change the tutorial, the completed version will no longer match. The relevant line in the completed project is: https://github.com/godotengine/godot-demo-projects/blob/master/2d/dodge_the_creeps/main.gd#L32-L36

[koubaa]

godotengine/godot-demo-projects#1151