Editor: Fix documentation for built-in scripts

[dalexeev]

Fixes the following bugs:

• Fixes @export script variables do not display tooltips when they are in built in script of node. #94338.

1. Standard tooltip is displayed instead of doc tooltip

I couldn't reproduce this, but it is apparently caused by the check:

godot/editor/connections_dialog.cpp

Lines 875 to 879 in b947c53

	Control *ConnectionsDockTree::make_custom_tooltip(const String &p_text) const {
	// If it's not a doc tooltip, fallback to the default one.
	if (p_text.contains("::")) {
	return nullptr;
	}

godot/editor/connections_dialog.cpp

Line 1520 in b947c53

String path = String(selected_node->get_path_to(target)) + " :: " + cd.method + "()";

2. Doc tooltip is empty for built-in classes and their members

This is because the Script Editor handles editing/saving external and built-in scripts inconsistently. As a result, Script.reload() was never called for built-in scripts (this method causes documentation to be regenerated in GDScript).

I'm not familiar with the Script Editor, so I tried to make minimal changes. I'm not sure about this part, please review and test carefully.

2.1. Documentation missing for built-in scripts

This is the real reason why tooltips didn't work. This fix may be inconvenient for some people, but we cannot make tooltips work without registering the built-in scripts documentation globally. Instead, we might add filters in the future (see godotengine/godot-proposals#4285).

After the fix:

3. EditorHelp does not handle :: in class names correctly

Added parsing instead of get_slice(":", index).

[KoBeWi]

Does this allow for built-in script documentation? I listed it as a limitation #55287, so resolving it would be nice.

[dalexeev]

Does this allow for built-in script documentation?

Yes, please test if it works correctly. But we should probably move the milestone to 4.4 because of possible regressions.

[KoBeWi]

I tested that it works, but the documentation is lost upon editor restart. If the page is opened on launch, it's empty:

You need to save the script/scene while the script is open in the script editor to regenerate the doc.

Though it's fine like that if we don't have doc cache for scripts. It's unreasonable to generate docs for every built-in script in the project. But it would be nice if at least it didn't require saving after opening a scene.

[dalexeev]

I tested that it works, but the documentation is lost upon editor restart.

See:

• Documentation generated by GDScript documentation comments dissapears. #72406
• The documentation for a class defined by the keyword 'class_name' does not appear when searching using the '(doc) Search Help' #86577