The three attrs LibreOffice's Format… dialog is mostly about, on both
sides of the bar. They live together on one TextStyle mark and a mark of
one type replaces that type whole, so each run's own attrs are the base of
the new one — recolouring leaves the font alone.
F3 was bound twice from here on: it now expands an AutoText shortcut where
the caret has one, as it does in both word processors, and finds the next
match otherwise.