XRENDERING-621: Make rendering errors translatables and extendables

* fix test

xwiki-rendering-transformations/xwiki-rendering-transformation-macro/src/test/java/org/xwiki/rendering/internal/transformation/macro/MacroTransformationTest.java

@@ -276,7 +276,7 @@ public void transformNotExistingMacro() throws Exception
         String expected = "beginDocument\n"
             + "beginMacroMarkerStandalone [notexisting] []\n"
             + "beginGroup [[class]=[xwikirenderingerror]]\n"
-            + "onWord [Unknown macro: notexisting.]\n"
+            + "onWord [Unknown macro: notexisting. Click on this message for details.]\n"
             + "endGroup [[class]=[xwikirenderingerror]]\n"
             + "beginGroup [[class]=[xwikirenderingerrordescription hidden]]\n"
             + "onVerbatim [The [notexisting] macro is not in the list of registered macros. "