Allow C# comments next to custom signals to be visible in the Godot UI.

[ArtixBot]

When creating a custom signal, I want to annotate it with the circumstances under which that signal is emitted, like so:

When viewing it in the Godot editor, I end up seeing this:

Ideally, I'd like to be able to see something like this (but with my own comment instead):

From the source code, it appears that much of the builtin signals have their documentation done via a separated XML file (https://github.com/godotengine/godot/blob/5f1e56ff26be4070496aa51095b9ac2f2b4f4ed8/doc/classes/Range.xml#L76). It'd be convenient to enable the Godot engine to use immediately-preceding comments for custom signal documentation as well.

[Calinou]

This is already available in GDScript (using comments that start with ## instead of #), but not in C#. I believe this also applies to other documentation comments in general.

PS: I think there's already another proposal tracking this, but I can't find it right now.
Edit: I found it, it's #5675.

[ArtixBot]

Ah, revising the title then.