C#: Remove outdated bits defines

These defines were removed in 4.0 but we missed them when we previously updated this documentation page.

tutorials/scripting/c_sharp/c_sharp_features.rst

@@ -111,7 +111,7 @@ For example, you can change code based on the platform:
 
         public override void _Ready()
         {
-    #if (GODOT_32 || GODOT_MOBILE || GODOT_WEB)
+    #if (GODOT_MOBILE || GODOT_WEB)
             // Use simple objects when running on less powerful systems.
             SpawnSimpleObjects();
     #else
@@ -157,8 +157,6 @@ Full list of defines
 
 * ``GODOT_REAL_T_IS_DOUBLE`` is defined when the ``GodotFloat64`` property is set to ``true``.
 
-* One of ``GODOT_64`` or ``GODOT_32`` is defined depending on if the architecture is 64-bit or 32-bit.
-
 * One of ``GODOT_LINUXBSD``, ``GODOT_WINDOWS``, ``GODOT_OSX``,
   ``GODOT_ANDROID``, ``GODOT_IOS``, ``GODOT_WEB``
   depending on the OS. These names may change in the future.