🧭 Order abbreviations by length

[agoose77]

This might not be the right place, or the best way to do this, but this PR orders abbreviations defined in the frontmatter by length (then by locale). As such, we no longer need to warn about the ordering.

[rowanc1]

This looks awesome, thanks @agoose77. 🚀

Can we move the sort code down a level so it is closer to where we do some other filtering? This should then be able to be shared a bit easily as the CLI code isn't going to be easy to share, e.g. with jupyterlab-myst and others.

Could you also run npm run changeset and write a short message that bumps the myst-transform and myst-cli packages (the myst-cli one will likely be manual once the changes are pushed down). This helps keep track of which packages need bumping.

[agoose77]

@rowanc1 thanks! I realised that my understanding of what the transform did was not quite right; initially I thought it wasn't sensible to move the logic to myst-transforms.

As such, I've moved this to a simple in-line sort, making this PR very small!

[rowanc1]

Thanks again @agoose77, excited to see these sorts of quality-of-life changes come to life! :)