List `@export_file` behavior change as a breaking change in the 4.3->4.4 upgrade page

[geekley]

Your Godot version: 4.4.stable

Issue description:
The change to how @export_file works from 4.3 to 4.4 was a breaking change!
Regardless of PR godotengine/godot#105414 (which adds @export_file_path to 4.5 for those who want the old behavior), the fact @export_file behavior changed needs to be added as a breaking change in Upgrading from Godot 4.3 to Godot 4.4. Hopefully this can be added right away to the online docs without depending on new Godot versions? (I don't know how this works)

URL to the documentation page:
https://docs.godotengine.org/en/stable/tutorials/migrating/upgrading_to_godot_4.4.html

See:

• @export_file need to allow you to keep the old behavior of setting it as res path instead of uid if desired (breaking change!) godot#104379
• Array of files is saved as uids in ProjectSettings since 4.4 godot#104818
• Add @export_file_path to export raw paths (no UID) godot#105414 (comment)
• This comment

For example:
In Breaking changes > Core and/or Behavior Changes > Core

Note

Annotation @export_file now prefers to store and return a uid://… instead of a res://… path. When changing a value in the inspector, its format will change to uid. This can make you have mixed uid and res paths even within an array.
Project settings will also store files as uid when you set or change a value.

Maybe also include something like:

In 4.5 you can keep the 4.3 behavior of @export_file by using @export_file_path instead.
In 4.4, the only way to preserve the old behavior is by manually setting the res://… path in *.tscn/*.tres files using a text editor whenever you need to change these fields.