Fix Rector, add Architecture test

[dansysanalyst]

Hi Nuno,

This PR upgrades Rector to fix the following error:

In addition, I included an ArchTest to showcase and promote Pest features.

I noticed Markdowns were failing lint, so I fix them.

MD022 - Headings should be surrounded by blank lines MD031 - Fenced code blocks should be surrounded by blank lines

Greetings,

Dan