Our perldoc shortcode needs updating

[dnmfarrell]

{{< perldoc "pack" >}}

Generates "https://perldoc.perl.org/pack.html" but since its overhaul the perldoc URL has changed: "https://perldoc.perl.org/5.30.0/functions/pack.html".

Apart from fixing the shortcode, I guess we should search and replace all perldoc links hardcoded in articles.

[cxw42]

I don't know if you want to broaden the range of external sites perl.com relies on, but https://perldoc.pl/functions/pack works without a version number, as another alternative.