Add examples of links to part of our lessons

**Work in progress. Don't merge it.**

Add examples of links to glossary entry and challenge.

## TODO

- [ ] Made changes based on comments
- [ ] Add changes to HTML files
- [ ] Squash changes to HTML into previous commits
Yeah, OK, we might need to link explicitly. But if we're going to do that, can we not add `{#ident}` to the definition term instead of auto-generating?