rules: manager: clarify doc string for NewGroupMetrics (#7084)
rules: manager: clarify doc string for NewGroupMetrics (#7084)

* rules: manager: clarify doc string for NewGroupMetrics

Signed-off-by: Muhammad Falak R Wani <2f5454d1df82a8c967e65c7fabca0c288c298f41@gmail.com>
alileza/prometheus,alileza/prometheus,kangwoo/prometheus,keegancsmith/prometheus,GoogleCloudPlatform/prometheus,GoogleCloudPlatform/prometheus,keegancsmith/prometheus,GoogleCloudPlatform/prometheus,kangwoo/prometheus,GoogleCloudPlatform/prometheus,Gouthamve/prometheus,kangwoo/prometheus,kangwoo/prometheus,Gouthamve/prometheus,keegancsmith/prometheus,alileza/prometheus,prometheus/prometheus,keegancsmith/prometheus,alileza/prometheus,prometheus/prometheus,prometheus/prometheus,prometheus/prometheus,prometheus/prometheus,Gouthamve/prometheus,alileza/prometheus,keegancsmith/prometheus,Gouthamve/prometheus,GoogleCloudPlatform/prometheus