patch 9.0.0090: no error when assigning bool to a string option

Problem:    No error when assigning bool to a string option with setwinvar().
Solution:   Give an error (closes #10766)

src/version.c

@@ -735,6 +735,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    90,
 /**/
     89,
 /**/