Add option to open online doc for selected class in script editor

[Gaktan]

When the script editor's current tab is a script (or no tab is opened):

When the current tab is a class:

There might be an issue if we try to open a custom class, but from what I can tell, it's not possible to open the documentation for a custom class in the editor. (At least I was not able to)

[Calinou]

Tested locally, it mostly works as expected. I've tested various classes such as HTTPClient, AnimatedSprite2D and so on. This feature makes sense to quickly access the online docs for the current class, which makes it easier to link to people (e.g. on forums).

One issue is that in user-defined classes, clicking Open in Online Docs will point to a nonexisting page. For instance, a class named Test will point me to https://docs.godotengine.org/en/latest/classes/class_test.html which doesn't exist. I suggest finding a way to disable this button for user-defined classes.

[Gaktan]

Yes indeed, I did not test this since I was not able to open the documentation for the custom classes in my project. I assumed it was not possible.

Can you clarify the steps you used to open a custom class's documentation?

[Calinou]

Can you clarify the steps you used to open a custom class's documentation?

Add this line above an extends declaration in a script:

class_name Test

Then use Search Help in the top-right corner of the script editor and search for Test, and open its page.

[Gaktan]

That's odd, it's not working for me:

Do I need to enable an option somewhere?

[Gaktan]

Nevermind, I figured it out. The documentation is not available for classes that only have private attributes and functions by the looks of it.

[Gaktan]

This now works with custom classes.
I have no idea if this fix works with custom C++ classes though, as I have no way to test this currently.

[Calinou]

The button now correctly displays Online Docs (instead of Open in Online Docs) when selecting a custom class named Test, but clicking it still opens the page https://docs.godotengine.org/en/latest/classes/class_test.html which doesn't exist.

[Chaosus]

Commits needs to be squashed (see https://docs.godotengine.org/en/latest/contributing/workflow/pr_workflow.html#the-interactive-rebase).

[Calinou]

Tested locally, it works as expected now. Code looks good to me.

[akien-mga]

Thanks! And congrats for your first merged Godot contribution 🎉