Moves @iter within a line, to a new character (not byte) offset.
The given character offset must be less than or equal to the number
of characters in the line; if equal, @iter moves to the start of the
next line. See [method@Gtk.TextIter.set_line_index] if you have a byte
index rather than a character offset.
Moves @iter within a line, to a new character (not byte) offset.
The given character offset must be less than or equal to the number of characters in the line; if equal, @iter moves to the start of the next line. See [method@Gtk.TextIter.set_line_index] if you have a byte index rather than a character offset.