Shell/3910

Restructure help center content.

[endlessm/eos-shell#3910]
Seems like these `<if:choose>` tags are messed up. The rendered content of this page is as follows:

> Many laptop computers have a hardware switch or key combination to turn Bluetooth on and off. If the Bluetooth hardware is turned off, you will not see a Bluetooth icon in the top bar. Look for a switch on your computer or a key on your keyboard. The keyboard key is often accessed with the help of the `Fn` key.

> > You only need to switch Visibility on if you are connecting to this computer from another device.