QMessageBox: leave the Option's underlying_type as the default, int

QFlags<Option> will anyway store the value in an `int`, so we gain
nothing from choosing quint8 as the fixed type, except artificially
limiting the number of possible future options to eight.

Found in API-review.

As a drive-by, put options one per line and add a trailing comma where
possible.

Pick-to: 6.6
Change-Id: I0ed588ea6c7912e50705af89c47e2cf7e2ee23a0
Reviewed-by: Volker Hilsheimer <volker.hilsheimer@qt.io>

src/gui/kernel/qplatformdialoghelper.h

@@ -405,7 +405,9 @@ protected:
 
 public:
     // Keep in sync with QMessageBox Option
-    enum class Option : quint8 { DontUseNativeDialog = 0x00000001 };
+    enum class Option {
+        DontUseNativeDialog = 0x00000001,
+    };
     Q_DECLARE_FLAGS(Options, Option);
     Q_FLAG(Options);
 

src/widgets/dialogs/qmessagebox.h

@@ -34,7 +34,7 @@ class Q_WIDGETS_EXPORT QMessageBox : public QDialog
     Q_PROPERTY(Options options READ options WRITE setOptions)
 public:
     // Keep in sync with MessageBoxOption in qplatformdialoghelper.h
-    enum class Option : quint8 {
+    enum class Option {
         DontUseNativeDialog = 0x00000001
     };
     Q_FLAG(Option)