Resolve review comments mike-ivs July

[svenvanderburg]

### Tasks
- [ ] Fix typos in supplementary material (will be fixed by mike-ivs)
- [ ] https://github.com/carpentries-incubator/deep-learning-intro/issues/491
- [ ] https://github.com/carpentries-incubator/deep-learning-intro/issues/483
- [ ] https://github.com/carpentries-incubator/deep-learning-intro/issues/484
- [ ] https://github.com/carpentries-incubator/deep-learning-intro/issues/485
- [ ] https://github.com/carpentries-incubator/deep-learning-intro/issues/486
- [ ] https://github.com/carpentries-incubator/deep-learning-intro/issues/500
- [ ] https://github.com/carpentries-incubator/deep-learning-intro/issues/502
- [ ] https://github.com/carpentries-incubator/deep-learning-intro/issues/487
- [ ] Palmer penguin links (will be picked up by Mike)
- [ ] https://github.com/carpentries-incubator/deep-learning-intro/issues/488
- [ ] https://github.com/carpentries-incubator/deep-learning-intro/issues/489
- [ ] Fix phrasing episode 2 (will be fixed by mike-ivs)
- [ ] https://github.com/carpentries-incubator/deep-learning-intro/issues/490

[mike-ivs]

Nice work on things so far! I'll get those PRs in shortly

[mike-ivs]

Apologies I biffed my commits into the same branch/PR: https://github.com/carpentries-incubator/deep-learning-intro/pull/514

This addresses the following:

• Fix typos in supplementary material (will be fixed by mike-ivs)
• Palmer penguin links (will be picked up by Mike)
• Fix phrasing episode 2 (will be fixed by mike-ivs)