Implement script editor hover hint with description

[Spartan322]

Supersedes #41502
Closes godotengine/godot-proposals#1393

Right now this is just a rebase and basic conversion of #41502 to master, (including CodeEdit changes) I tried to ensure it has a bare minimum functionality testing it, it does properly display the hints, but some things are as of now missed, and I seem to have not gotten documentation to work properly, it'll stay a draft until I can clean this up a bit.

This is no longer a direct conversion of #41502, there are things I missed in implementing this proposal in full, I'm not entirely confident this is even a totally correct implementation, hence why I left the initial convert commit (despite being somewhat bugged) unchanged for now and the big reason its still a draft, (the initial conversion was still fairly bugged too and sort of re-implemented rich text popup functionality in CodeEdit) however this does implement many more improvements, alongside some few bugs. I committed this to get eyes on it and to improve this beyond what I've been able to do from this point.

Improvements

• Hover hints appear on the line below the first character of the hovered symbol
• Supports hover hints for annotations
• Uses editor settings to enable and modify the hint display
• Relies upon RichTextLabel inside a PopupPanel to display hint text
  • The hint can't currently be focused but it does use a duplicate of the _add_text_to_rt function from /editor/editor_help.cpp.
• Local variables should be able to support descriptions
• All inbuilt classes can display hover hints with descriptions
• CodeEdit only has a new symbol_hovered(symbol : String, symbol_column_line : Vector2) signal that ScriptTextEditor relies on for hover hints
• Added get_word_line_column_at_pos(mouse_pos : Vector2) -> Vector2i to TextEdit
  • Duplicates get_word_at_pos but retrieves the line and column of the first character of the word, used by the symbol_hovered signal to abstract the need for retrieving the mouse position.

Known Issues

• The RichTextLabel may overflow the popup in some cases
• Short symbols may erroneously be wrapped by the RichTextLabel inside the popup
• Hovered symbols may feel incorrect since they do not account for the last character, for single character identifiers this can result in a very deceptively tiny region to activate the hint. (this appears to be the fault of get_word_at_pos)
• Symbols inside a $ may be treated as the type they are named after regardless of whether they're actually based on that type (for example if you named a Popup as PopupMenu, the symbol hint for $PopupMenu will display a hint for PopupMenu)

[Calinou]

Tested locally (rebased on top of master 851bc64), it works. I think this is a good start, and having this feature will improve the script editor's usability a lot.

simplescreenrecorder-2023-07-17_00.08.40.mp4

There are a few usability issues I noticed:

• Script descriptions don't seem to appear for user-provided properties and methods, even if you restart the editor.

• Strings that match a function name (without parentheses after the function name) will display the function popup (see the end of the above video).

• The hover duration seems pretty low – I frequently accidentally make the popup appear when I don't want to. This is annoying, as the popup also blocks mouse input including scrolling (it scrolls the block if possible, instead of the script).

  • In comparison, it takes roughly twice as long for hover tooltips to show up in VS Code.

• Colors are hard to read on a light editor theme, even after restarting the editor:

simplescreenrecorder-2023-07-17_00.10.28.mp4

These issues need to be addressed somehow before this PR can be merged.

[Spartan322]

All right, I'll see what I can do.

[dalexeev]

• @Spartan322 Note that there is another PR GDScript Symbol Tooltip #80044.

[Spartan322]

Yeah I'm aware, I've gotten busy and haven't had as much time to work on this.