Updates to Formatting & Syntax

Hi there,

I've taken the liberty of fixing some typos and formatting errors in the docs. These are just some of the errors/inconsistencies that caught my attention while adding kali-desktop-i3-gaps to the metapackages docs (68995900).

Please let me know if the changes are acceptable for you. If they are, I will be taking a look at the docs and improve their overall format.