patch 8.2.4492: no error if an option is given a value with ":let &opt = val"

Problem:    No error if an option is given an invalid value with
            ":let &opt = val".
Solution:   Give the error. (closes #9864)

src/version.c

@@ -754,6 +754,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    4492,
 /**/
     4491,
 /**/