[NativeMenu] Implement native popup menu support on Windows.

[bruvzg]

Partial NativeMenu (since there's no "global menu") for Windows, useful for status indicator (tray icon) context menus, but can be used with any popup (PopupMenu).

[KoBeWi]

The menu goes under task bar, which makes it difficult to use with tray icons:

Also it seems to be tied to the main window. When you minimize it, the menu can't appear.
Also also clicking outside the menu does not close it.

EDIT:
Also, not sure how controllable is that, but the menu does not follow the system theme. It should be dark in my case.

[bruvzg]

The menu goes under task bar
Also it seems to be tied to the main window. When you minimize it, the menu can't appear.
Also also clicking outside the menu does not close it.

Should be fixed, as well as support dark mode.

[KoBeWi]

I didn't check the code, but did some brief testing and it works correctly.

The documentation could use some code examples.

[bruvzg]

Added a usage example to the docs, also added prefer_native_menu property to the PopupMenu to use it as a wrapper for native popups (more convenient that doing it from the code).

[Mickeon]

I'm fine with this but how does anyone else feel about it, over the more explicit var menu = null?

[bruvzg]

Seems redundant to me (at least for non-typed code, and all doc examples seems to be non-typed).

[akien-mga]

Thanks!

[KoBeWi]

So I didn't test the latest changes to PopupMenu, because I assumed they'd be alright, but there is error spam when opening editor:

[aaronfranke]

This caused a regression in the macOS global menu: #89496

[jsjtxietian]

there is error spam when opening editor:

I got this too.