CppEditor: Adjust Title in preprocessor dialog.

Now its more consistent with the other text in this dialog.

Change-Id: I424428a6fb892a2f0be2a3c6b11ae652ea39c679
Reviewed-by: Nikolai Kosjar <nikolai.kosjar@digia.com>

src/plugins/cppeditor/cpppreprocessordialog.ui

@@ -11,7 +11,7 @@
    </rect>
   </property>
   <property name="windowTitle">
-   <string>Additional C++ Preprocess Directives</string>
+   <string>Additional C++ Preprocessor Directives</string>
   </property>
   <layout class="QVBoxLayout" name="verticalLayout">
    <item>