Doc: move imageviewer docs from headers to cpp files

Use standard wording for function docs. Use valid
QDoc commands (\a instead of \param, for example).

Change-Id: I556fdbf686f2f54138617d6784c650a1d973513c
Reviewed-by: Eike Ziller <eike.ziller@digia.com>

src/plugins/imageviewer/imagevieweractionhandler.cpp

@@ -114,6 +114,11 @@ void ImageViewerActionHandler::createActions()
                       QKeySequence());
 }
 
+/*!
+    Creates a new action with the internal id \a actionId, command id \a id,
+    and keyboard shortcut \a key, and registers it in the action manager.
+*/
+
 void ImageViewerActionHandler::registerNewAction(int actionId, const Core::Id &id,
     const QString &title, const QKeySequence &key)
 {