C# symbol lookup

[poohcom1]

Is your feature request related to a problem? Please describe.
Currently, symbol lookup is only supported for GDScript autoloads.

Describe the solution you'd like

• Solution A: Full symbol lookup with C# regex
• Solution B: Partial symbol lookup by only opening script file (to line 0)
  • Clicking either the base class or any member should open up the script. Helpful if the autoload is a global shortcut.

Additional context

Since the current symbol lookup system relies on regex search, I'm aware it is a lot harder to achieve accurate symbol lookup with a C-like syntax. I think a "good enough" lookup could work, assuming common conventions when it comes to formatting. But if we want to avoid inaccurate regex search altogether, a basic script lookup would still be useful, as this is what the Godot code editor also does for global C# class.