Add a parameter comment

apm-sniffer/apm-agent-core/src/main/java/org/skywalking/apm/agent/core/plugin/AbstractClassEnhancePluginDefine.java

@@ -20,6 +20,7 @@ public abstract class AbstractClassEnhancePluginDefine {
      *
      * @param transformClassName target class.
      * @param builder byte-buddy's builder to manipulate target class's bytecode.
+     * @param classLoader load the given transformClass
      * @return the new builder, or <code>null</code> if not be enhanced.
      * @throws PluginException, when set builder failure.
      */