Update port reinstallation instruction on wiki

[Joshua Root]

On 3/10/2023 08:17, Jimmy Wong wrote:
> On Oct 2, 2023 at 8:13 AM +0100, Joshua Root <jmr at macports.org>, wrote:
> 
>         This won't necessarily restore the variants of non-requested ports
>         correctly, and will sometimes install the same port multiple
>         times (a
>         requested port that is a dep of another requested port can be first
>         installed with its default variants, then again with its previously
>         requested variants.)
> 
> 
> Yes it will. The requested.txt files produced this way come with 
> variants.
You can't possibly restore the state of non-requested ports when you 
only record information about requested ones.

If you understand the process well enough to evaluate the tradeoff of 
not restoring quite all the state, you are not really the target 
audience for the Migration instructions. If you don't mind dealing with 
the occasional problem due to opportunistic use, you're free to simply 
run 'sudo port upgrade outdated' after reinstalling base.

- Josh