Fixed unwanted wrapping of code editor tooltips

Turns out the <nobr> actually caused wrapping in some cases because the
tag made the QToolTip turn on its wrapping feature due to the text being
rich text. So avoid adding it to plain text tooltips unnecessarily.

Reviewed-by: hunger
Task-number: QTCREATORBUG-1169

src/plugins/cppeditor/cpphoverhandler.cpp

@@ -427,7 +427,7 @@ void CppHoverHandler::updateHelpIdAndTooltip(TextEditor::ITextEditor *editor, in
                         .arg(m_toolTip);
         }
         editor->setContextHelpId(m_helpId);
-    } else if (!m_toolTip.isEmpty()) {
+    } else if (!m_toolTip.isEmpty() && Qt::mightBeRichText(m_toolTip)) {
         m_toolTip = QString(QLatin1String("<nobr>%1")).arg(m_toolTip);
     }
 }