Update the getting started 3d tutorial for godot 4.x

I followed the entire 3d tutorial with godot 4.x and the changes to the
docs repo were small. The largest change was needing to replace the
outdated links to the old starter project with assets. Since there was
no longer a non-complete starter project, I made a PR to
godot-docs-project-starters. That would need to be reviewed and merged
first before the link to the new starter project zip file would be
valid.

New starter/assets project PR:
godotengine/godot-docs-project-starters#9

Author: russellsanborn

getting_started/first_3d_game/01.game_setup.rst

@@ -8,16 +8,15 @@ importing the start assets and setting up the game scene.
 
 We've prepared a Godot project with the 3D models and sounds we'll use for this
 tutorial, linked in the index page. If you haven't done so yet, you can download
-the archive here: `Squash the Creeps assets
-<https://github.com/godotengine/godot-3d-dodge-the-creeps/releases/tag/1.1.0>`__.
+the archive here: `Squash the Creeps assets <https://github.com/godotengine/godot-docs-project-starters/releases/download/latest-4.x/3d_squash_the_creeps_starter.zip>`_.
 
 Once you downloaded it, extract the .zip archive on your computer. Open the
 Godot Project Manager and click the *Import* button.
 
 .. image:: img/01.game_setup/01.import_button.webp
 
 In the import popup, enter the full path to the freshly created directory
-``squash_the_creeps_start/``. You can click the *Browse* button on the right to
+``3d_squash_the_creeps_starter/``. You can click the *Browse* button on the right to
 open a file browser and navigate to the ``project.godot`` file the folder
 contains.
 
@@ -108,7 +107,7 @@ the viewport.
 We're going to move the ground down so we can see the floor grid. To do this, the grid snapping feature can be used.
 Grid snapping can be activated 2 ways in the 3D editor.
 The first is by pressing the *Use Snap* button (or pressing the :kbd:`Y` key).
-The second is by selecting a node, dragging a handle on the gizmo **then** holding :kbd:`Ctrl` while still clicking to enable snapping as long as :kbd:`Ctrl` is held. 
+The second is by selecting a node, dragging a handle on the gizmo **then** holding :kbd:`Ctrl` while still clicking to enable snapping as long as :kbd:`Ctrl` is held.
 
 .. image:: img/01.game_setup/use_snap.webp
 

getting_started/first_3d_game/03.player_movement_code.rst

@@ -143,7 +143,7 @@ call its ``normalized()`` method.
 .. tabs::
  .. code-tab:: gdscript GDScript
 
-   #func _physics_process(delta):
+   func _physics_process(delta):
        #...
 
        if direction != Vector3.ZERO:

getting_started/first_3d_game/img/01.game_setup/04.start_assets.webp

@@ -33,7 +33,7 @@ This tutorial is for beginners who followed the complete getting started series.
 We'll start slow with detailed instructions and shorten them as we do similar
 steps. If you're an experienced programmer, you can browse the complete demo's
 source code here: `Squash the Creep source code
-<https://github.com/godotengine/godot-3d-dodge-the-creeps>`__.
+<https://github.com/godotengine/godot-demo-projects/tree/master/3d/squash_the_creeps>`__.
 
 .. note::
 
@@ -44,7 +44,7 @@ source code here: `Squash the Creep source code
 
 We prepared some game assets so we can jump straight to the code. You can
 download them here: `Squash the Creeps assets
-<https://github.com/godotengine/godot-3d-dodge-the-creeps/releases/tag/1.1.0>`__.
+<https://github.com/godotengine/godot-docs-project-starters/releases/download/latest-4.x/3d_squash_the_creeps_starter.zip>`__.
 
 We will first work on a basic prototype for the player's movement. We will then
 add the monsters that we'll spawn randomly around the screen. After that, we'll