The System Menu on the right end of the top bar is supposed to have lines for me to "switch users, lock screen, log out, suspend, restart, or shutdown" my computer. But there is no line to restart the computer, so I have to shut it down and then start it again manually. How do I put back the "restart" option?
You could have also shut it down by pressing Ctrl+Alt+T to open the terminal, and running
sudo shutdown -r now.
Never mind -- I just discovered that if you click on "Shut Down," a window pops up that has a curly arrow with no explanation under it, and if you move the cursor over to it, the word "Restart" appears. Very counterintuitive!