Fixes #5224 * Split the [reference documentation](https://canonical-snapcraft.readthedocs-hosted.com/en/latest/reference/architectures/#supported-architectures) about supported architectures by base. * The difference between bases is that support for `i386` and `powerpc` (not `ppc64el`) was dropped in `core22` and newer bases. * "Supported locally" and "supported by launchpad" are the same for core22 and newer bases. For core20, "powerpc" is locally supported. **Support for core20 and core22 and higher is now correctly split according to the request.** * Update outdated docs or point them to read the docs: * https://snapcraft.io/docs/reference-architectures#supported-architectures * https://snapcraft.io/docs/build-from-github **The links above were broken and what seemed to be the corresponding doc now was already pointing to the supported architectures.** I spotted this issue that looked like a good first issue, I stay available for any further modifications. I believe the meta description update is not relevant in this case and I suppose that I should wait for the approval of this PR to update the relevant release notes. Best regards. --- - [x] I've followed the [contribution guidelines](https://github.com/canonical/snapcraft/blob/main/CONTRIBUTING.md). - [x] I've signed the [CLA](http://www.ubuntu.com/legal/contributors/). - [x] I've successfully run `make lint && make test`. - [x] I've added or updated any relevant documentation. - [ ] In documents I changed, I [added a meta description](https://canonical-starflow.readthedocs-hosted.com/how-to/add-a-page-meta-description/) if one was missing. - [ ] I've updated the relevant release notes.