Format according to styleguide, add fixes and solution to advanced task

[ppxasjsm]

Looks mostly good. I think there are a couple of things that are my bad because they are not well done in the style guide (will update)

TOC -> Table of Content let's write this out. Use a heading for the git cheat sheet options (I think this was included in the original version of this)

I'll update the Style guide accordingly....sorry for the faff.

[ppxasjsm]

Sorry git cheatsheet formatting is fine, but lets have it at the end of the preamble before putting all the important imports for the session!