CppTools: Fixed tooltip for Enable Doxygen blocks

Change-Id: Ie047782cde63bd64b6a52747ee2cd7d4fc102b88
Reviewed-by: Orgad Shaneh <orgads@gmail.com>
Reviewed-by: Nikolai Kosjar <nikolai.kosjar@digia.com>

src/plugins/cpptools/completionsettingspage.ui

@@ -205,7 +205,7 @@
       <item>
        <widget class="QCheckBox" name="enableDoxygenCheckBox">
         <property name="toolTip">
-         <string>Automatically create a Doxygen comment upon pressing enter after a /** or /*!</string>
+         <string>Automatically create a Doxygen comment upon pressing enter after a /**, /*!, //! or ///</string>
         </property>
         <property name="text">
          <string>Enable Doxygen blocks</string>