patch 8.2.4460: Vim9: wrong error for defining dict function

Problem:    Vim9: wrong error for defining dict function.
Solution:   Explicitly check for trying to define a dict function.
            (closes 9827)
diff --git a/src/errors.h b/src/errors.h
index 5f2685a..72c0d12 100644
--- a/src/errors.h
+++ b/src/errors.h
@@ -3010,7 +3010,8 @@
 	INIT(= N_("E1180: Variable arguments type must be a list: %s"));
 EXTERN char e_cannot_use_underscore_here[]
 	INIT(= N_("E1181: Cannot use an underscore here"));
-// E1182 unused
+EXTERN char e_cannot_define_dict_func_in_vim9_script_str[]
+	INIT(= N_("E1182: Cannot define a dict function in Vim9 script: %s"));
 EXTERN char e_cannot_use_range_with_assignment_operator_str[]
 	INIT(= N_("E1183: Cannot use a range with an assignment operator: %s"));
 #endif