savegame ex.: use NSDMI, =default the default ctor

Modernizes the code.

Task-number: QTBUG-108857
Change-Id: I6ddf1de3699506ffc0fc4b1034ab48defafcf174
Reviewed-by: Mårten Nordheim <marten.nordheim@qt.io>
(cherry picked from commit 35b94f8b4349581c548b7aac2e858750072efa19)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>

examples/corelib/serialization/savegame/character.cpp

@@ -6,10 +6,8 @@
 #include <QMetaEnum>
 #include <QTextStream>
 
-Character::Character() :
-    mLevel(0),
-    mClassType(Warrior) {
-}
+Character::Character()
+    = default;
 
 Character::Character(const QString &name,
                      int level,

examples/corelib/serialization/savegame/character.h

@@ -37,8 +37,8 @@ public:
     void print(int indentation = 0) const;
 private:
     QString mName;
-    int mLevel;
-    ClassType mClassType;
+    int mLevel = 0;
+    ClassType mClassType = Warrior;
 };
 //! [0]