Remove comment that hasn't been true for 5 years

llvm-svn: 206725

llvm/include/llvm/Option/Arg.h

@@ -27,10 +27,7 @@ class ArgList;
 /// \brief A concrete instance of a particular driver option.
 ///
 /// The Arg class encodes just enough information to be able to
-/// derive the argument values efficiently. In addition, Arg
-/// instances have an intrusive double linked list which is used by
-/// ArgList to provide efficient iteration over all instances of a
-/// particular option.
+/// derive the argument values efficiently.
 class Arg {
   Arg(const Arg &) LLVM_DELETED_FUNCTION;
   void operator=(const Arg &) LLVM_DELETED_FUNCTION;