ProjectExplorer: Reference icon for Code Style settings page

Task-number: QTCREATORBUG-6357

Change-Id: Ia622a133208ce1df605a10cef809f259dc5a0274
Reviewed-by: Eike Ziller <eike.ziller@digia.com>

src/plugins/projectexplorer/projectexplorer.qrc

@@ -23,6 +23,7 @@
         <file>images/compile_error.png</file>
         <file>images/compile_warning.png</file>
         <file>images/BuildSettings.png</file>
+        <file>images/CodeStyleSettings.png</file>
         <file>images/RunSettings.png</file>
         <file>images/EditorSettings.png</file>
         <file>images/ProjectDependencies.png</file>