4.2.0 release notes: fix formatting

Author: michaelklishin

release-notes/4.2.0.md

@@ -147,7 +147,7 @@ than their AMQP 0-9-1 and AMQP 1.0 counterparts.
 See the [Upgrading guide](https://www.rabbitmq.com/docs/upgrade) for documentation on upgrades and [GitHub releases](https://github.com/rabbitmq/rabbitmq-server/releases)
 for release notes of individual releases.
 
-This release series supports upgrades from `4.1.x`, 4.0.x` and `3.13.x`.
+This release series supports upgrades from `4.1.x`, `4.0.x` and `3.13.x`.
 
 [Blue/Green Deployment](https://www.rabbitmq.com/docs/blue-green-upgrade)-style upgrades are avaialble for migrations
 from RabbitMQ `3.12.x` series.