Fixed formatting (missing comma)

src/validation/rules/default_values_of_correct_type.rs

@@ -18,7 +18,7 @@ impl<'a> Visitor<'a> for DefaultValuesOfCorrectType {
             if !ctx.registry.types.contains_key(vtype_name.as_str()) {
                 ctx.report_error(
                     vec![variable_definition.pos],
-                    format!(r#"Unknown type "{}""#, vtype_name)
+                    format!(r#"Unknown type "{}""#, vtype_name),
                 );
                 return;
             }