Remove unneeded includes

Change-Id: I83a6dc6ba33f7f8e1f6b1babbf60c69554435a0a
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@qt.io>

src/plugins/help/helpwidget.cpp

@@ -52,9 +52,6 @@
 
 #include <QCoreApplication>
 #include <QHBoxLayout>
-#include <QHelpEngine>
-#include <QHelpSearchEngine>
-#include <QHelpSearchQuery>
 #include <QMenu>
 #include <QPrinter>
 #include <QPrintDialog>

src/plugins/help/textbrowserhelpviewer.cpp

@@ -35,7 +35,6 @@
 #include <QApplication>
 #include <QClipboard>
 #include <QContextMenuEvent>
-#include <QHelpEngine>
 #include <QKeyEvent>
 #include <QMenu>
 #include <QScrollBar>