Method push_undo

src/editor/buffer.rs:378–387

(&mut self, record: UndoRecord)

    }

    fn push_undo(&mut self, record: UndoRecord) {
        if record.inserted.is_empty() && record.deleted.is_empty() {
            return;
        }
        self.redo_stack.clear();
        self.undo_stack.push_back(record);
        if self.undo_stack.len() > MAX_UNDO {
            self.undo_stack.pop_front();
        }
    }

    fn move_previous_word(&mut self) {
        let mut idx = self.cursor_char_idx();