GUI: add editor toolbar display option (Bug #46705) * libgui/src/m-editor/file-editor.cc, libgui/src/m-editor/file-editor.h (file_editor::show_toolbar): new function (file_editor::notice_settings): set toolbar state from settings (file_editor::construct): add show toolbar action * libgui/src/settings-dialog.cc (settings_dialog::settings_dialog): set toolbar checkbox from settings (settings_dialog::write_changed_settings): save toolbar state to settings * libgui/src/settings-dialog.ui: added showtoolbar checkbox

gnulib-hg = gnulib-hg