[docs] Remove reference to adding namespace to coordinator config (#2977

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Co-authored-by: Chris Chinchilla <chris@chronosphere.io>

site/content/quickstart/docker.md

@@ -93,8 +93,6 @@ This quickstart uses the _{{% apiendpoint %}}database/create_ endpoint that crea
 
 You can create [placements](/docs/operational_guide/placement_configuration/) and [namespaces](/docs/operational_guide/namespace_configuration/#advanced-hard-way) separately if you need more control over their settings.
 
-The `namespaceName` argument must match the namespace in the `local` section of the `M3Coordinator` YAML configuration. If you [add any namespaces](/docs/operational_guide/namespace_configuration) you also need to add them to the `local` section of `M3Coordinator`'s YAML config.
-
 In another terminal, use the following command.
 
 {{< tabs name="create_placement_namespace" >}}