patch 9.1.1117: there are a few minor style issues

Problem:  there are a few minor style issues
Solution: fix the issues (Hirohito Higashi)

closes: #16646

Signed-off-by: Hirohito Higashi <h.east.727@gmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/src/vim9class.c b/src/vim9class.c
index 8220536..b5e3a13 100644
--- a/src/vim9class.c
+++ b/src/vim9class.c
@@ -2489,7 +2489,7 @@
 
     if (success && is_enum && num_enum_values == 0)
 	// Empty enum statement. Add an empty "values" class variable
-	enum_add_values_member(cl, &classmembers, 0, &type_list);
+	success = enum_add_values_member(cl, &classmembers, 0, &type_list);
 
     /*
      * Check a few things