[css3-syntax] Simplify parsing diagrams.

Author: SimonSapin

css3-syntax/Diagrams.src.html

@@ -201,13 +201,13 @@ <h3>Parsing</h3>
 
 add('Declaration/at-rule list', Diagram(
     NT('WS*'),
-    Optional(Choice(0,
+    Choice(0,
         Sequence(
             Optional(NT('Declaration')),
             Optional(Sequence(NT(';'), NT('Declaration/at-rule list')))),
         Sequence(
             NT('At-rule'),
-            NT('Declaration/at-rule list'))))));
+            NT('Declaration/at-rule list')))));
 
 add('Declaration', Diagram(
     NT('IDENT'), NT('WS*'), NT('COLON'), NT('WS*'),