patch 8.2.3537: mode() does not return the right value in 'operatorfunc'

Problem:    mode() does not return the right value in 'operatorfunc'.
Solution:   Reset finish_op while calling 'operatorfunc'.

src/version.c

@@ -757,6 +757,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    3537,
 /**/
     3536,
 /**/