Chore: Tidy `README.md` Screenshots and Markdown Fails

[nelsonic]

Reading through the README.md at 3a8ae45 there are quite a few inconsistencies and Markdown fails

e.g: Old screenshot: https://github.com/dwyl/phoenix-liveview-counter-tutorial/tree/3a8ae4560fde21bfb138c0d064e7f24c9c19b51f#run-the-app

There are 11 instances of the `` (double-backtic) character:

This is because VSCodium was inserting double yesterday while I was trying to fix things ... 🤦‍♂️

Todo

• [x] Do a quick read-through of the README.md and all the code 👀
• [x] Fix all the inconsistencies 📝
• [ ] Create PR 🆕

[nelsonic]

Final version running on localhost:

[nelsonic]

Ready for continuous delivery/deployment when @dependabot makes updates. 👌

[nelsonic]

Fixed by #169 ✅