Fix links in 4.2.0 release notes

Author: ansd

release-notes/4.2.0.md

@@ -10,11 +10,11 @@ RabbitMQ 4.2.0 is a new feature release.
 Incoming and outgoing messages can now be intercepted on the broker.
 This works for AMQP 1.0, AMQP 0.9.1, and MQTT.
 
-What the interceptor does is entirely up to its implementation - it can validate message metadata, add annotations, or perform arbitrary side effects.
-Custom interceptors can be developed and integrated via [plugins](./plugins).
+What the interceptor does is entirely up to its implementation, for example it can validate message metadata, add annotations, or perform arbitrary side effects.
+Custom interceptors can be developed and integrated via [plugins](https://www.rabbitmq.com/docs/next/plugins).
 
 Two new optional built-in interceptors were added to RabbitMQ:
 1. Timestamps for outgoing messages
 2. Setting client ID of publishing MQTT client
 
-Detailed information can be found in the [Message Interceptor](https://www.rabbitmq.com/docs/next/message-inteceptor) documentation.
+Detailed information can be found in the [Message Interceptor](https://www.rabbitmq.com/docs/next/message-interceptors) documentation.