Feature #11916: Update doc for 3.0
Update doc wrt. Tails in GNOME Boxes in Stretch
- clicking on the hamburger menu in the top-right corner of the window
- selecting "Properties" from the drop-down menu
- toggling the sliding switch "Share Clipboard" from "On" to "Off" in the "General" settings tab in the opened window
- closing the settings by clicking on the "x" icon in the top right of the window
advanced_topics/virtualization/preferences-system-symbolic.png can be removed while doing this (the menu button changed to a hamburger menu, the file is not used anywhere else).