Missing documented App::shared()

[eugenesvk]

Docs mention App::shared() call to get the shared app, but I couldn't find the actual shared function anywhere.

https://docs.rs/cacao/latest/cacao/appkit/trait.AppDelegate.html

fn did_finish_launching(&self)
Fired when the application has finished launching. Unlike most other “load” lifecycle events in this framework, you don’t get a reference to an app here - if you need to call through to your shared application, then used the App::shared() call.