Document limitations in members API

- display of group_saml_identity attribute
- display of member email attribute

doc/api/members.md

@@ -172,6 +172,7 @@ Example response:
   "avatar_url": "https://www.gravatar.com/avatar/c2525a7f58ae3776070e44c106c48e15?s=80&d=identicon",
   "web_url": "http://192.168.1.8:3000/root",
   "access_level": 30,
+  "email": "john@example.com",
   "expires_at": null,
   "group_saml_identity": null
 }
@@ -209,6 +210,7 @@ Example response:
   "avatar_url": "https://www.gravatar.com/avatar/c2525a7f58ae3776070e44c106c48e15?s=80&d=identicon",
   "web_url": "http://192.168.1.8:3000/root",
   "access_level": 30,
+  "email": "john@example.com",
   "expires_at": null,
   "group_saml_identity": null
 }
@@ -247,6 +249,7 @@ Example response:
   "web_url": "http://192.168.1.8:3000/root",
   "expires_at": "2012-10-22T14:13:35Z",
   "access_level": 30,
+  "email": "john@example.com",
   "group_saml_identity": null
 }
 ```
@@ -284,6 +287,7 @@ Example response:
   "web_url": "http://192.168.1.8:3000/root",
   "expires_at": "2012-10-22T14:13:35Z",
   "access_level": 40,
+  "email": "john@example.com",
   "group_saml_identity": null
 }
 ```
@@ -320,6 +324,7 @@ Example response:
   "web_url": "http://192.168.1.8:3000/root",
   "expires_at": "2012-10-22T14:13:35Z",
   "access_level": 40,
+  "email": "john@example.com",
   "override": true
 }
 ```
@@ -356,6 +361,7 @@ Example response:
   "web_url": "http://192.168.1.8:3000/root",
   "expires_at": "2012-10-22T14:13:35Z",
   "access_level": 40,
+  "email": "john@example.com",
   "override": false
 }
 ```
@@ -383,3 +389,9 @@ curl --request DELETE --header "PRIVATE-TOKEN: <your_access_token>" "https://git
 ## Give a group access to a project
 
 See [share project with group](projects.md#share-project-with-group)
+
+## Limitations
+
+The `group_saml_identity` attribute is only visible to a group owner for [SSO enabled groups](../user/group/saml_sso/index.md).
+
+The `email` attribute is only visible to a group owner who manages the user through [Group Managed Accounts](../user/group/saml_sso/group_managed_accounts.md).