bug#69410: 30.0.50; [WISHLIST] Use-package: allow :ensure to accept package spec instead of separate :vc keyword

[No Wayman]

I think it would be cleaner to allow use-package's :ensure keyword 
to accept the arguments the :vc keyword currently does. e.g.

;; Install EXAMPLE package from ELPA archive
(use-package example :ensure t)

;; Install EXAMPLE package from source
(use-package example :ensure (:url 
"https://www.forge.com/maintainer/example";))

My reasoning is that this has greater potential to work across 
multiple package managers.
Instead of each package manager adding their own use-package 
keyword (e.g. :vc, :straight, :elpaca), they can all interpret the 
:ensure keyword's value. It would make things simpler for package 
maintainers offering example declarations and users switching 
between package managers.

Thoughts?