Merge #15768: gui: Add close window shortcut

f5a3a5b9ab gui: Add close window shortcut (Miguel Herranz)

Pull request description:

  CMD+W is the standard shortcut in macOS to close a window without
  exiting the program.

  This adds support to use the shortcut in both main and debug windows.

ACKs for top commit:
  jonasschnelli:
    Tested ACK f5a3a5b9ab
  hebasto:
    ACK f5a3a5b9ab, tested on Linux Mint 19.3 by manually opening available dialogs and sub-windows, and applying the `Ctrl+W` shortcut. Also tested with "Minimize on close" option enabled / disabled.

Tree-SHA512: 39851f6680cf97c334d5759c6f8597cb45685359417493ff8b0566672edbd32303fa15ac4260ec8ab5ea1458a600a329153014f25609e1db9cf399aa851ae2f9

src/qt/utilitydialog.cpp

@@ -10,6 +10,8 @@
 
 #include <qt/forms/ui_helpmessagedialog.h>
 
+#include <qt/guiutil.h>
+
 #include <clientversion.h>
 #include <init.h>
 #include <util/system.h>
@@ -102,6 +104,8 @@ HelpMessageDialog::HelpMessageDialog(interfaces::Node& node, QWidget *parent, bo
         ui->scrollArea->setVisible(false);
         ui->aboutLogo->setVisible(false);
     }
+
+    GUIUtil::handleCloseWindowShortcut(this);
 }
 
 HelpMessageDialog::~HelpMessageDialog()
@@ -141,6 +145,8 @@ ShutdownWindow::ShutdownWindow(QWidget *parent, Qt::WindowFlags f):
         tr("%1 is shutting down...").arg(PACKAGE_NAME) + "<br /><br />" +
         tr("Do not shut down the computer until this window disappears.")));
     setLayout(layout);
+
+    GUIUtil::handleCloseWindowShortcut(this);
 }
 
 QWidget* ShutdownWindow::showShutdownWindow(QMainWindow* window)