Godot Project Setup: Add step to set GDScript Export Mode to Text

> Mod Hooks only work if the source code is readable. With Godot 4.3, binary tokenization has been reintroduced and is the default export setting.
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> * [GDScript: Reintroduce binary tokenization on export godotengine/godot#87634](https://github.com/godotengine/godot/pull/87634)
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> For game developers integrating the Mod Loader, adding a step in the documentation to switch to text mode will be sufficient.
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> For self-setup, we will need to use GDRE to decompile scripts that require a hook.
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> Script extensions are not affected by this.

https://github.com/GodotModding/godot-mod-loader/issues/535

Needs to be added here:
https://wiki.godotmodding.com/guides/integration/godot_project_setup/