CPlusPlus: New code model icons

Change-Id: I9ad6445319d85ffb652377a00256a68d56754352
Reviewed-by: David Schulz <david.schulz@theqtcompany.com>
Reviewed-by: Eike Ziller <eike.ziller@theqtcompany.com>

src/plugins/texteditor/codeassist/genericproposalwidget.cpp

@@ -275,6 +275,7 @@ GenericProposalWidgetPrivate::GenericProposalWidgetPrivate(QWidget *completionWi
     , m_assistant(0)
     , m_autoWidth(true)
 {
+    m_completionListView->setIconSize(QSize(16, 16));
     connect(m_completionListView, &QAbstractItemView::activated,
             this, &GenericProposalWidgetPrivate::handleActivation);