Comment parsing: followup to r184610: allow multiple \returns

Remove unneeded member in CommentSema, add a test for the XML schema (the
schema already allowed multiple paragraphs in <ResultDiscussion>, but there
were no tests for that), fix HTML generation (it is not allowed to have <p>
inside <dl>).

llvm-svn: 184652
diff --git a/clang/tools/libclang/CXComment.cpp b/clang/tools/libclang/CXComment.cpp
index b96ca1c..583b850 100644
--- a/clang/tools/libclang/CXComment.cpp
+++ b/clang/tools/libclang/CXComment.cpp
@@ -787,10 +787,10 @@
   }
 
   if (Parts.Returns.size() != 0) {
-    Result << "<dl>";
+    Result << "<div class=\"result-discussion\">";
     for (unsigned i = 0, e = Parts.Returns.size(); i != e; ++i)
       visit(Parts.Returns[i]);
-    Result << "</dl>";
+    Result << "</div>";
   }
 
   Result.flush();