Documentation updates: descriptions for local_volume and volume_type (#…

…275)

Some improvements for selectel_mks_cluster_v1 docs.

website/docs/r/mks_nodegroup_v1.html.markdown

@@ -64,9 +64,9 @@ resource "selectel_mks_nodegroup_v1" "nodegroup_1" {
 
 * `volume_gb` (Optional) Volume size in GB for each node. Can be skipped only when flavor_id is set and local_volume is `true`. Changing this creates a new node group.  Learn more about [Configurations](https://docs.selectel.ru/cloud/managed-kubernetes/node-groups/configurations/).
 
-* `volume_type` (Optional) Type of an OpenStack blockstorage volume for each node. Can be skipped only when `flavor_id` is set and flavor contains disk specification. Changing this creates a new node group.  Available volume types are `fast`, `basic`, and `universal`. The format is `<volume_type>`.`<availability_zone>`. Learn more about [Network volumes](https://docs.selectel.ru/cloud/servers/volumes/about-network-volumes/).
+* `volume_type` (Optional) Type of an OpenStack blockstorage volume for each node. Can be skipped only when `flavor_id` is set and the flavor properties contain additional specifications for a local volume. Changing this creates a new node group. Available volume types are `fast`, `basic`, and `universal`. The format is `<volume_type>`.`<availability_zone>`. Learn more about [Network volumes](https://docs.selectel.ru/cloud/servers/volumes/about-network-volumes/).
 
-* `local_volume` (Optional) Specifies if nodes use a local volume. Conflicts with flavors that have `local_volume` specs. Changing this creates a new node group. Boolean flag, the default value is false.
+* `local_volume` (Optional) Specifies if nodes use a local volume. Cannot be used with the flavors that have specifications for a local volume. Changing this creates a new node group. Boolean flag, the default value is false.
 
 * `flavor_id` (Optional) Unique identifier of an OpenStack flavor for all nodes in the node group. Changing this creates a new node group. Learn more about [Flavors](https://docs.selectel.ru/cloud/managed-kubernetes/node-groups/configurations/#create-node-group-with-prebuilt-cloud-server-configuration).