[css-grid] Update DoC

Author: fantasai

css-grid/issues-wd-20150917.bsi

@@ -136,8 +136,8 @@ Issue 15.
 Summary:  Example is confusing
 From:     Manuel Rego Casasnovas
 Comment:  https://lists.w3.org/Archives/Public/www-style/2015Dec/0110.html
-Response:
-Open
+Response: https://lists.w3.org/Archives/Public/www-style/2016May/0181.html
+Closed:   Accepted
 Verified:
 Resolved: Editorial
 ----