- Move from Common Tasks to Configuration Guides, since most users will
just use the GUI
- Rename from `change-timezone-terminal.md` to `change-time-zone.md`
(1) because we don't want multiple time zone documents for terminal
and non-terminal usage and (2) to make the orthography of "time zone"
consistent; update title and permalink accordingly
- Make heading syntax consistent
- Add heading
- Fix code block syntax
- Fix typo
- Add page to ToC
