[libc++][NFC] Fix incorrect comment for vector::assign(iter, iter) test

libcxx/test/std/containers/sequences/vector/vector.cons/assign_iter_iter.pass.cpp

diff --git a/libcxx/test/std/containers/sequences/vector/vector.cons/assign_iter_iter.pass.cpp b/libcxx/test/std/containers/sequences/vector/vector.cons/assign_iter_iter.pass.cpp
index 9b52885..b6aeba4 100644
--- a/libcxx/test/std/containers/sequences/vector/vector.cons/assign_iter_iter.pass.cpp
+++ b/libcxx/test/std/containers/sequences/vector/vector.cons/assign_iter_iter.pass.cpp
@@ -8,7 +8,8 @@
 
 // <vector>
 
-// void assign(size_type n, const_reference v);
+// template <class InputIt>
+// constexpr void assign(InputIt first, InputIt last);
 
 #include <vector>
 #include <algorithm>