Quick clarification about unequal groups (#2877)

* Quick clarification about unequal groups
* Changes after review

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Co-authored-by: Simon Dew <[email protected]>

Author: BKaneAtWork

modules/learn/pages/clusters-and-availability/groups.adoc

@@ -90,7 +90,7 @@ A number of constraints come into play when allocating active and replica vBucke
 
 Not all the constraints can be satisfied when the buckets are allocated across uneven groups.
 In this scenario, the `active balance` and `rack-zone` constraints will take priority:
-when the vBucket map is generated, we will ensure that there are approximately the same number of active vBuckets on each cluster and that replicas of a given vBucket must reside in separate groups.
+when the vBucket map is generated, we will ensure that there are approximately the same number of active vBuckets on each node in the cluster and that replicas of a given vBucket must reside in separate groups.
 
 The following illustration shows how vBuckets are distributed across two groups: Group 1 contains four nodes, while Group 2 contains five.