patch 8.2.0657: Vim9: no check if called variable is a FuncRef

Problem:    Vim9: no check if called variable is a FuncRef.
Solution:   Add a type check.

src/version.c

@@ -746,6 +746,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    657,
 /**/
     656,
 /**/