resource/gitlab_group: document groups without parent group limitation on SaaS

Closes: #647

Author: timofurrer

docs/resources/group.md

@@ -3,18 +3,18 @@
 page_title: "gitlab_group Resource - terraform-provider-gitlab"
 subcategory: ""
 description: |-
-  This resource allows you to create and manage GitLab groups.
-  Note your provider will need to be configured with admin-level access for this resource to work.
-  Upstream API: GitLab Groups API https://docs.gitlab.com/ee/api/groups.html
+  The gitlab_group resource allows to manage the lifecycle of a group.
+  -> On GitLab SaaS, you must use the GitLab UI to create groups without a parent group. You cannot use this provider nor the API to do this.
+  Upstream API: GitLab REST API docs https://docs.gitlab.com/ee/api/groups.html
 ---
 
 # gitlab_group (Resource)
 
-This resource allows you to create and manage GitLab groups.
+The `gitlab_group` resource allows to manage the lifecycle of a group.
 
-Note your provider will need to be configured with admin-level access for this resource to work.
+-> On GitLab SaaS, you must use the GitLab UI to create groups without a parent group. You cannot use this provider nor the API to do this.
 
-**Upstream API**: [GitLab Groups API](https://docs.gitlab.com/ee/api/groups.html)
+**Upstream API**: [GitLab REST API docs](https://docs.gitlab.com/ee/api/groups.html)
 
 ## Example Usage
 

internal/provider/resource_gitlab_group.go

@@ -17,9 +17,11 @@ import (
 
 var _ = registerResource("gitlab_group", func() *schema.Resource {
 	return &schema.Resource{
-		Description: "This resource allows you to create and manage GitLab groups.\n\n" +
-			"Note your provider will need to be configured with admin-level access for this resource to work.\n\n" +
-			"**Upstream API**: [GitLab Groups API](https://docs.gitlab.com/ee/api/groups.html)",
+		Description: `The ` + "`gitlab_group`" + ` resource allows to manage the lifecycle of a group.
+
+-> On GitLab SaaS, you must use the GitLab UI to create groups without a parent group. You cannot use this provider nor the API to do this.
+
+**Upstream API**: [GitLab REST API docs](https://docs.gitlab.com/ee/api/groups.html)`,
 
 		CreateContext: resourceGitlabGroupCreate,
 		ReadContext:   resourceGitlabGroupRead,