[Documentation] Fix changelog entries for version 3.11.1.

Signed-off-by: Giacomo Marciani <[email protected]>

Author: gmarciani

CHANGELOG.md

@@ -7,10 +7,11 @@ This file is used to list changes made in each version of the AWS ParallelCluste
 ------
 
 **CHANGES**
-- Pyxis is now disabled by default and it must be manually enabled on the head node.
+- Pyxis is now disabled by default, so it must be manually enabled as documented in the product documentation.
 
 **BUG FIXES**
 - Fix an issue in the way we configure the Pyxis Slurm plugin in ParallelCluster that can lead to job submission failures.
+  https://github.com/aws/aws-parallelcluster/issues/6459
 
 3.11.0
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