Improve log warning - add offender

A log warning without the offender mentioned is meaningless. Now added.

Ref #17591

Author: lbruun

modules/openapi-generator/src/main/java/org/openapitools/codegen/DefaultCodegen.java

@@ -7094,7 +7094,7 @@ public boolean convertPropertyToBoolean(String propertyKey) {
         } else if (booleanValue instanceof String) {
             result = Boolean.parseBoolean((String) booleanValue);
         } else {
-            LOGGER.warn("The value (generator's option) must be either boolean or string. Default to `false`.");
+            LOGGER.warn("The '{}' value (generator's option) must be either boolean or string. Default to `false`.", propertyKey);
         }
         return result;
     }