chore(code-style-guide): Add bad unwrap example for tests

Author: Techassi

modules/contributor/pages/code-style-guide.adoc

@@ -791,7 +791,15 @@ fn deserialize() {
     let input: String = serde_yaml::from_str("my string").expect("input string must deserialize");
     assert_eq(&input, "my string");
 }
+----
+
+====
+
+[WARNING.code-rule,caption=Examples of incorrect code for this rule]
+====
 
+[source,rust]
+----
 #[test]
 fn serialize() {
     let serialized = serde_yaml::to_string(&String::from("my string")).unwrap();