Update multi-threaded rendering setting path

Changes from "Rendering > Threads > Thread Model", which used to be the old path for Godot 3.x, to "Rendering > Driver > Thread Model", which is the current one for Godot 4.x.

tutorials/performance/thread_safe_apis.rst

@@ -55,7 +55,7 @@ Rendering
 ---------
 
 Instancing nodes that render anything in 2D or 3D (such as Sprite) is *not* thread-safe by default.
-To make rendering thread-safe, set the **Rendering > Threads > Thread Model** project setting to **Multi-Threaded**.
+To make rendering thread-safe, set the **Rendering > Driver > Thread Model** project setting to **Multi-Threaded**.
 
 Note that the Multi-Threaded thread model has several known bugs, so it may not be usable
 in all scenarios.