Moves backward to the next toggle (on or off) of the
GtkTextTag tag, or to the next toggle of any tag if
tag is NULL. If no matching tag toggles are found,
returns FALSE, otherwise TRUE. Does not return toggles
located at iter, only toggles before iter. Sets iter
to the location of the toggle, or the start of the buffer
if no toggle is found.
Moves backward to the next toggle (on or off) of the GtkTextTag tag, or to the next toggle of any tag if tag is NULL. If no matching tag toggles are found, returns FALSE, otherwise TRUE. Does not return toggles located at iter, only toggles before iter. Sets iter to the location of the toggle, or the start of the buffer if no toggle is found.