More work on porting to Godot4 -- Part 2

[limbonaut]

I've marked some warnings to be ignored - particularly those that complain about overriding native class declaration. It seems intentional, since those methods are later used in other places of the plugin.

[mphe]

There is a reason why "overriding native class declaration" warning exists and why it is treated as error by default.
That is because not all engine methods are marked virtual and therefore not overridable. Instead they get shadowed. That means they will not necessarily get called as you would expect. This behavior already existed in 3.x but Godot didn't emit a warning about it.
See also the discussion in godotengine/godot#55024.

So, ignoring those warnings is not a fix. These cases of shadowing need to be actually fixed by changing the implementation.
I saw you already fixed some of it, e.g. the part for adding child nodes. So there are only a few cases left where we need to find a better solution.

Also, the duplicate() overrides in various files are most certainly not necessary anymore, since godotengine/godot#58031 was fixed.

I guess it's better to split this PR up in multiple parts. I will create some issues to keep track of those parts that need more sophisticated fixes.

[mphe]

Apart from hiding those override warnings, I like the rest and would merge it, if you separate it.

[limbonaut]

Alright, I left those warnings as is. Fixed another case of shadowing in one of the panels.

There's one more thing. It seems that Z Index section is hidden in GUI edge panel and remains unused. I checked with upstream, and it seems to be the case there. I left it as is for now.

[mphe]

Merged, good work!