[Editor] Generate and display documentation for the properties generated by PropertyListHelper.

[bruvzg]

Adds documentation for the dynamic properties generated by PropertyListHelper (e.g, menu items).

[KoBeWi]

I actually made proposal for this, not sure if you had seen it: godotengine/godot-proposals#13965

In my proposal I suggested having a separate list for dynamic properties, since they are a group. So instead of item_{index}/text you'd have something like

Property Group Items:
Prefix: item_
Count: item_count

bool disabled
 description
String text
 description
etc.

(somewhat similar to how enums are organized)

The Count information would also allow to get rid of Note: in every description. However it's rather significant change over the current implementation (it'd also affect XML structure), so probably up to discussion.

The implementation itself looks good, aside from missing Open Documentation button in the context menu for dynamic properties. Also needs rebase to include recently added Curve helpers.

[bruvzg]

In my proposal I suggested having a separate list for dynamic properties, since they are a group. So instead of item_{index}/text you'd have something like

Not sure if its worth adding new list for the PropertyListHelper properties. But there are a lot of other dynamic properties generated by get_property_list with less uniform structure, and if we'll add docs support for these it would make sense to have a separate category for more flexibility.

[KoBeWi]

Not a fan of having a note in every description, but the implementation itself is fine. It can be improved upon later if needed.

[AThousandShips]

Approving the new documentation entries

[akien-mga]

Thanks!