patch 9.0.1516: cannot use special keys in <Cmd> mapping

Problem:    Cannot use special keys in <Cmd> mapping.
Solution:   Do allow for special keys in <Cmd> and <ScriptCmd> mappings.
            (closes #12326)

src/version.c

@@ -695,6 +695,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1516,
 /**/
     1515,
 /**/