Fix the ChangeLog for my previous commit

Fixes: 66ce32bb2a8 ("Fix the ChangeLog for my previous commit")

From-SVN: r276922

gcc/ChangeLog

+2019-10-12  Palmer Dabbelt  <palmer@sifive.com>
+
+	* doc/extend.texi (Alternate Keywords): Change "-std=c11" to "a
+	later standard."
+
 2019-10-12  John David Anglin  <danglin@gcc.gnu.org>
 
 	* gcc/config/pa/pa.c (pa_option_override): Remove trailing comma