communicating actual working directory to the editor (#44298) * file-editor-tab.cc (file-editor-tab.cc): init new _ced variable storing current editor directory, do not store directory in _file_name; (set_current_directory): new slot for setting current editor directory; (handle_context_menu_edit): use _ced for current directory; (valid_file_name): just check whether name is empty; (save_file_as): set directory to current edit directory; * file-editor-tab.h: new variable _ced; new slot for setting _ced, * file-editor.cc (update_octave_directory): new slot for setting current editor directory to wirking directory; (handle_editor_state_changed): do not ced from current file name; (add_file_editor_tab) connect new signal for setting directory to related slot in file_editor_tab * file-editor.h: new slot and new signal updating directory * main-window.cc (change_directory): do not call update directory function in file_browser_window because the latter is notified by a signal now; (construct_octave_qt_link): connect change_directory_signal from octave_qt_link to appropriate slots in editor and file browser

% Increase save size to run @seealso macro for Octave documentation
save_size = 10000