This partially addresses #737. The Pebble page used to lead users to the GitHub repo. There is now a documentation page for Pebble, so I have updated this accordingly. I have also fixed some minor spelling issues. --- - [x] I've followed the [contribution guidelines](https://github.com/canonical/rockcraft/blob/main/CONTRIBUTING.md). - [x] I've signed the [CLA](http://www.ubuntu.com/legal/contributors/). - [ ] I've successfully run `make lint && make test`. - [ ] I've added or updated any relevant documentation.