[FEATURE REQUEST] Manifest mode "vcpkg install <package>" should suggest the use of add port

[feenix1]

This is a quality of life feature that I think would be helpful. The common package manager syntax of 'install package_name' is convenient, and I think choosing to use manifest mode should not take away that convenience.

'add port package_name', which is basically exactly what I was looking for, should be suggested in the error using 'vcpkg install' in manifest mode instead of manually editing vcpkg.json.