Doc: move Class View plugin docs to .cpp files.

QDoc does not find docs in the .h files.
Use \brief only for namespaces, classes, enums, and properties.
Use standard wording for \brief and \fn.
Use \a and \c according to guidelines.

Fix grammar and style.

Change-Id: Ib685a03c97ef38661ecc156f61d70085514357fc
Reviewed-by: Erik Verbruggen <erik.verbruggen@digia.com>

src/plugins/classview/classviewnavigationwidgetfactory.cpp

@@ -45,6 +45,23 @@ static NavigationWidgetFactory *factoryInstance;
 
 ///////////////////////////////// NavigationWidgetFactory //////////////////////////////////
 
+/*!
+    \class NavigationWidgetFactory
+    \brief The NavigationWidgetFactory class implements a singleton instance of
+    the INavigationWidgetFactory for the Class View.
+
+    Supports the \c setState public slot for adding the widget factory to or
+    removing it from \c ExtensionSystem::PluginManager.
+
+    Also supports the \c widgetIsCreated and \c stateChanged signals.
+*/
+
+/*!
+    \fn void NavigationWidgetFactory::widgetIsCreated()
+
+    Informs that the widget factory created a widget.
+*/
+
 NavigationWidgetFactory::NavigationWidgetFactory()
 {
     factoryInstance = this;
@@ -92,10 +109,8 @@ Core::NavigationView NavigationWidgetFactory::createWidget()
 
 
 /*!
-   \brief Get a settings prefix for the specified position
-   \param position Position
-   \return Settings prefix
- */
+   Returns a settings prefix for \a position.
+*/
 static QString settingsPrefix(int position)
 {
     return QString::fromLatin1("ClassView/Treewidget.%1/FlatMode").arg(position);