Focus the show notes when you click a show #564

[garyb1]

Changes

1. Wrapped the ShowLink Link into a new ShowLink component
2. Added tabIndex of -1 to the showNotes container div to make it programatically focusable.
3. Changes the anchor tab to a button so we get those native keyboard behaviours by default. Some styling needed to be added to make it look as before.
4. On ShowLink button click, we programatically set focus to the showNotes container.

[vercel[bot]]

This pull request is being automatically deployed with Vercel (learn more).
To see the status of your deployment, click below or on the icon next to each commit.

🔍 Inspect: https://vercel.com/wesbos/syntax/7nna7hi2m
✅ Preview: https://syntax-git-focus-show-notes-564.wesbos.vercel.app