Comment 19 for bug 2037642

Added text to the release notes [1] detailing Pi 5 support, including the planned SRU of libcamera support. Can others double-check the raspberry pi sections look reasonable, and let me know if we want to mention anything else specific?

I've also updated the "known issues" section, removing a couple of bits (totem now works and the audio output selection is now sane out of the box), and adding others (slide corruption on the pi4 during installation). Again, if there's anything missing that should be mentioned please either let me know or feel free to add it yourself!

[1]: https://discourse.ubuntu.com/t/mantic-minotaur-release-notes/35534