patch 7.4.911

Problem:    t_Ce and t_Cs are documented but not supported. (Hirohito Higashi)
Solution:   Define the options.

src/version.c

@@ -741,6 +741,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    911,
 /**/
     910,
 /**/