[VPlan] Fix first-lane comment in sinkScalarOperands (NFC) (#166347)

To follow-up on a post-commit review.

Author: artagnon

llvm/lib/Transforms/Vectorize/VPlanTransforms.cpp

@@ -198,8 +198,8 @@ static bool sinkScalarOperands(VPlan &Plan) {
     VPSingleDefRecipe *SinkCandidate;
     std::tie(SinkTo, SinkCandidate) = WorkList[I];
 
-    // All recipe users of the sink candidate must be in the same block SinkTo
-    // or all users outside of SinkTo must have only their first lane used. In
+    // All recipe users of SinkCandidate must be in the same block SinkTo or all
+    // users outside of SinkTo must only use the first lane of SinkCandidate. In
     // the latter case, we need to duplicate SinkCandidate.
     auto UsersOutsideSinkTo =
         make_filter_range(SinkCandidate->users(), [SinkTo](VPUser *U) {