gui: Add select all menu (Bug #41797) * libgui//qterminal/libqterminal/QTerminal.h: Add selectAll popup menu and virtual function. * libgui/qterminal/libqterminal/unix/QUnixTerminalImpl.cpp,h: Add selectAll function. * libgui/qterminal/libqterminal/unix/TerminalView.cpp,h: add selectAll function. * libgui/qterminal/libqterminal/win32/QWinTerminalImpl.cpp,h: Add selectAll function. * libgui/src/documentation-dock-widget.cc,h: Add selectAll function. * libgui/src/files-dock-widget.cc,h: Add selectAll function. * libgui/src/history-dock-widget.cc,h: Add selectAll function. * libgui/src/m-editor/file-editor-tab.cc,h: Add select_all function and signal. * libgui/src/m-editor/file-editor.cc,h: Add request_selectall and selectAll function, add Edit->select all menu. * libgui/src/main-window.cc: add selectAll function, selectAll menu. * libgui/src/octave-dock-widget.cc,h: Add virtual selectAll function and connect to mainwindow selectall signal. * libgui/src/qtinfo/webinfo.cc,h: Add selectAll function. * libgui/src/workspace-view.cc,h: Add selectAll function.

--- a/libgui/qterminal/libqterminal/unix/QUnixTerminalImpl.cpp
+++ b/libgui/qterminal/libqterminal/unix/QUnixTerminalImpl.cpp
@@ -205,6 +205,12 @@
     m_terminalView->pasteClipboard();
 }
 
+void QUnixTerminalImpl::selectAll()
+{
+    m_terminalView->selectAll();
+}
+
+
 QString QUnixTerminalImpl::selectedText ()
 {
   return m_terminalView->selectedText ();