Doc: Add "required" qualifier to methods

[timothyqiu]

Closes godotengine/godot-proposals#9824

Whether a virtual method is required has been marked by #93311. This PR:

• Makes editor help & online doc show a required qualifier next to virtual if the method is required.
• Removes the manually added [b]Optional.[/b] and [b]Required.[/b] from the descriptions of related methods.

[Mickeon]

If you didn't do it I would have, to be honest.
Although I have a hunch that the "required" qualifier is much more important than the rest, and should be highlighted as such in some way.

[AThousandShips]

Makes sense, and has associated tooltips so should be complete

[Mickeon]

Like, this is a fine addition, but I still stand by my prior comment. Perhaps it could be formatted in bold in the built-in class reference?

[dalexeev]

I would prefer "abstract", which is a common term for virtual methods with no default implementation. See also:

• GDScript: Add abstract methods #106409

I wanted to make this a step up from GDScript's abstract methods, since changing the behavior if you didn't implement the required native methods would be a compatibility break. So, looking at it another way, a separate qualifier might make sense too, although it's more confusing and less unified.

[timothyqiu]

I have a hunch that the "required" qualifier is much more important than the rest, and should be highlighted as such in some way.

We don't have abstract methods yet, so currently "required" is a soft requirement, hinting that a minimum implementation should at least overwrite these methods to function properly without any error printed, I think.

The editor theme & editor help currently does not have the concept of a bold code font. It could be a dedicated PR if appropriate.

[dalexeev]

To be clear: I don't mind the way you did it initially. The abstract qualifier implies stronger requirements and some compatibility breakage. For example, a GDScript class extending EditorHelp without implementing the _run() method and not marked as abstract should produce a compile-time error.

Another difference is that you can't instantiate an abstract GDScript class at all, while you can instantiate EditorScript without an attached script (the difference between abstract and virtual classes in Godot terms).

Considering that even custom abstract GDScript methods are highly unlikely to make it into 4.5, unifying native abstract methods in 4.5 is out of the question. I think it would be acceptable to introduce the required qualifier and then replace it with abstract. If it only concerns Editor Help, not XML files.

Major changes

[timothyqiu]

OK, reverted to the "required" version.

It sounds like abstract methods are meant to be implemented as a GDScript functionality rather than core functionality, but we'll see about that later.

[akien-mga]

Makes sense to me. I suggest being a bit more explicit in the message, other suggestions welcome.

[dsnopek]

Thanks, this is a really great idea!

[akien-mga]

Thanks!