tweak first line

popl19/response2.md

 We thank the reviewers for their very helpful feedback and will revise
-the paper accordingly. In particular, we will expand on the motivation
-for using CBPV and clearly state our contributions.
+the paper accordingly. Especially, we will try to make the
+introduction more generally accessible.
 
 1. **Reviewer C** says "Moreover, the paper doesn't produce any particular
    equalities that one might want to reason with while programming."