renamed extension point schema

plugins/org.yakindu.sct.ui.editor/plugin.xml

@@ -3,7 +3,7 @@
 <plugin>
 	<!-- Extension Points -->
 	
-   <extension-point id="org.yakindu.sct.ui.editor.expressions" name="org.yakindu.sct.ui.editor.expressions" schema="schema/org.yakindu.sct.ui.editor.expressions.exsd"/>
+   <extension-point id="expressions" name="org.yakindu.sct.ui.editor.expressions" schema="schema/expressions.exsd"/>
   
     <!-- Editor -->