events: add back changes from c0a6320

lib/internal/events/slow_event_emitter.js

@@ -177,7 +177,7 @@ SlowEventEmitter.prototype.addListener = function addListener(type, listener, pr
       // No error code for this since it is a Warning
       const w = genericNodeError(
         `Possible EventEmitter memory leak detected. ${existing.length} ${String(type)} listeners ` +
-        `added to ${inspect(target, { depth: -1 })}. Use emitter.setMaxListeners() to increase limit`,
+        `added to ${inspect(target, { depth: -1 })}. MaxListeners is ${m}. Use emitter.setMaxListeners() to increase limit`,
         { name: 'MaxListenersExceededWarning', emitter: target, type: type, count: existing.length });
       process.emitWarning(w);
     }