More succinct centering of blockquotes in ConTeXt

style_green.tex

@@ -66,8 +66,7 @@ $endif$
 
 \setupdelimitedtext
   [blockquote]
-  [before={\blank[medium]\startalignment[middle]},
-   after={\blank[medium]\stopalignment},
+  [before={\setupalign[middle]},
    indentnext=no,
   ]