IR: Fix comment from r213824

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@213836 91177308-0d34-0410-b5e6-96231b3b80d8

Author: dexonsmith

include/llvm/IR/Value.h

@@ -470,7 +470,7 @@ class Value {
   ///
   /// \return the first element in the list.
   ///
-  /// \note Completely ignores \a Prev (doesn't read, doesn't update).
+  /// \note Completely ignores \a Use::Prev (doesn't read, doesn't update).
   template <class Compare>
   static Use *mergeUseLists(Use *L, Use *R, Compare Cmp) {
     Use *Merged;