VSCode-style preview tabs: files opened from the treeview with a single
click open in a preview tab (titled "~ name ~") that is reused for the
next file opened and becomes a permanent tab as soon as it is edited,
double-clicked or dragged.
Verified against the running editor: single-click opens preview, opening
another file replaces it, editing promotes it to a permanent tab.
Pinned to lite-xl-plugins @ 31eef29 (see debian/extra/README.source).
vhaudiquet
273965ef0b