De-duplicate BBCodes information

[Ivorforce]

Referring to #9996 (comment), BBCodes are currently documented 3 5 times:

• GDScript documentation comments
• GDExtension documentation system
• Class reference primer
• RichTextLabel
• Class Reference Translation

It might be better to have a separate, independent page for bbcodes. If the info from RichTextLabel should not be merged into the ones for the documentation system, at least the others can be merged together as they really are the same use-case.

[tetrapod00]

Related: godotengine/godot-proposals#10339

[paddy-exe]

The documentation for the GDExtension docs system can't be merged with the others because not all BBCode features are support in that system. Before creating my docs PR I tried out pretty much every tag there is.

[Ivorforce]

@paddy-exe That's good to have confirmed.

But do you know if it's true for the class references and script documentation system too? I would have thought at least those 3 would use the same subset of bbcodes.

[paddy-exe]

@Ivorforce From what I am seeing looking at these pages it seems to me like the GDExtension, GDScript system use the same system underneath.
The RichTextLabel docs are more in-depth since it supports all the tags available.
The class reference doesn't reference any [img] tag support. Not sure if it does support this. Otherwise I doubt that this would get merged into the engine anyways.
The class reference translation docs only explains a short section what should/should not be translated so I think that should be fine.

[Ivorforce]

Ok, sounds good. Then i propose we create a new page for bbcodes / formatting in class references, link it from all 4 pages (translation too), and keep page-specific info to a minimum (eg in the translation Page, the info about how to work with these tags in translation). RichTextLabel can be linked for context but should be kept separate.