Update glossary

[JostMigenda]

would it be worth adding Array Broadcasting (or anything else, it's probably been somewhat overlooked as vectorisation isn't in their either) to the glossary?

https://github.com/RSE-Sheffield/pando-python/blob/main/learners/reference.md

Originally posted by @Robadob in #57 (comment)

Let’s open this as a separate issue, since we didn’t think about it across my earlier PRs, either; so we may have missed glossary items across other episodes.

[Robadob]

Let’s open this as a separate issue, since we didn’t think about it across my earlier PRs, either; so we may have missed glossary items across other episodes.

I'll probably do a full course read through before we move to beta and try to catch anything then.