Update website wiki and git build instructions for testers
Wanted to try out the git version, looked at the README.md, which only said:
GNOME Calendar is a simple and beautiful calendar application for GNOME. We give a lot of attention to details, and as such, design is an essential and ongoing effort. The wiki is [here] : https://wiki.gnome.org/Design/Apps/Calendar
Given that the wiki link is not the actual link to GNOME Calendar's wiki website (https://wiki.gnome.org/Apps/Calendar), then I'm assuming what I see on https://wiki.gnome.org/Apps/Calendar/Download and therefore https://wiki.gnome.org/Apps/Calendar/JHBuild is outdated as well in light of the port to Meson etc.?
- Update the Wiki pages
- No typos