Various improvements suggested by Duncan

llvm-svn: 48325
diff --git a/llvm/lib/VMCore/ParameterAttributes.cpp b/llvm/lib/VMCore/ParameterAttributes.cpp
index 7501a35..b5fb832 100644
--- a/llvm/lib/VMCore/ParameterAttributes.cpp
+++ b/llvm/lib/VMCore/ParameterAttributes.cpp
@@ -77,7 +77,7 @@
 class ParamAttributeListImpl : public FoldingSetNode {
   unsigned RefCount;
   
-  // ParamAttrsList is uniqued, these should not be publicly available
+  // ParamAttrsList is uniqued, these should not be publicly available.
   void operator=(const ParamAttributeListImpl &); // Do not implement
   ParamAttributeListImpl(const ParamAttributeListImpl &); // Do not implement
   ~ParamAttributeListImpl();                        // Private implementation