Merge upstream changes

[ns-rse]

Pulling in up-stream changes which adds support for Citation File Formats in the footer.

[Robadob]

Guess we're merging from upstream now

[ns-rse]

I was about to go through the README.md and address #7 and noticed we we're behind so had a look at what had changed. Figured that pulling from upstream would help with #6 so thought it worth comiting to updating/tracking changes from upstream regularly as I found out yesterday at the UK Carpentries monthly meetup about a PR to incorporate mermaid diagrams and as I've used quite a few of these in my material I'm keen to use that as soon as its available.

I'll solve the conflicts.

[Robadob]

I thought I rebased last week (and just forced pushed to main), but maybe I didn't fetch upstream first.