Adwaita: Add "selected but not focused" styles
Sometimes it's confusing if multiple lists or treeviews contain a selected row, but only one of them will react to key navigation input.
One example of this is the filechooser. Starting a file chooser dialog shows a nicely highlighted blue "Recent" row in the sidebar, but pressing e.g. the arrow down key will NOT change the selected row in the sidebar, but instead in the treeview.
It would be nice it if was clear where the keyboard input is going to go in such situations.