Documentation: update Q_DISABLE_COPY documentation

Q_DISABLE_COPY annotates the functions as deleted but this was not
mentioned in the documentation.
As a drive-by adjust some indentations.

Change-Id: I808fe3f1ce9f949d2ba41436661569ab0f2a9f73
Reviewed-by: Sze Howe Koh <szehowe.koh@gmail.com>
Reviewed-by: Paul Wicking <paul.wicking@qt.io>

src/corelib/doc/snippets/code/src_corelib_global_qglobal.cpp

@@ -595,8 +595,7 @@ namespace QT_NAMESPACE {
 //! [43]
 class MyClass : public QObject
 {
-
-  private:
+private:
     Q_DISABLE_COPY(MyClass)
 };
 
@@ -605,22 +604,21 @@ class MyClass : public QObject
 //! [44]
 class MyClass : public QObject
 {
-
-  private:
-     MyClass(const MyClass &);
-     MyClass &operator=(const MyClass &);
+private:
+    MyClass(const MyClass &) = delete;
+    MyClass &operator=(const MyClass &) = delete;
 };
 //! [44]
 
 //! [45]
-  QWidget w = QWidget();
+QWidget w = QWidget();
 //! [45]
 
 //! [46]
-        // Instead of comparing with 0.0
-                qFuzzyCompare(0.0,1.0e-200); // This will return false
-        // Compare adding 1 to both values will fix the problem
-                qFuzzyCompare(1 + 0.0, 1 + 1.0e-200); // This will return true
+// Instead of comparing with 0.0
+qFuzzyCompare(0.0, 1.0e-200); // This will return false
+// Compare adding 1 to both values will fix the problem
+qFuzzyCompare(1 + 0.0, 1 + 1.0e-200); // This will return true
 //! [46]
 
 //! [47]