Mention new warnings for ProjectSettings.add_property_info() in Upgrading to Godot 4.5

The behavior is the same as before, but it now prints a warning
whereas it previously ignored the `usage` key silently.

Author: Calinou

tutorials/migrating/upgrading_to_godot_4.5.rst

@@ -204,6 +204,17 @@ new behavior, you must change the "Naming Version" option at the bottom of the I
 Core
 ~~~~
 
+.. note::
+
+    :ref:`ProjectSettings.add_property_info() <class_ProjectSettings_method_add_property_info>`
+    now prints a warning when the dictionary parameter has missing keys or invalid keys.
+    Most importantly, it will now warn when a ``usage`` key is passed, as this key is not used.
+    This was also the case before 4.5, but it was silently ignored instead.
+    As a reminder, to set property usage information correctly, you must use
+    :ref:`ProjectSettings.set_as_basic() <class_ProjectSettings_method_set_as_basic>`,
+    :ref:`ProjectSettings.set_restart_if_changed() <class_ProjectSettings_method_set_restart_if_changed>`,
+    or :ref:`ProjectSettings.set_as_internal() <class_ProjectSettings_method_set_as_internal>` instead.
+
 .. note::
 
     In C#, ``StringExtensions.PathJoin`` now avoids adding an extra path separator when the original string is empty,