update doc

docs/admin_api/user_admin_api.md

@@ -149,10 +149,11 @@ Body parameters:
   granting them access to the Admin API, among other things.
 - `deactivated` - **bool**, optional. If unspecified, deactivation state will be left unchanged.
 
-  Note: the `password` field must also be set if both of the following are true:
-  - `deactivated` is set to `false` and the user was previously deactivated (you are reactivating this user)
-  - Users are allowed to set their password on this homeserver (both `password_config.enabled` and
-    `password_config.localdb_enabled` config options are set to `true`).
+  Note:
+  - For the password field there is no strict check of the necessity for its presence.
+    It is possible to have active users without a password, e.g. when authenticating with OIDC is configured.
+    You must check yourself whether a password is required when reactivating a user or not.
+  - It is not possible to set a password if the config option `password_config.localdb_enabled` is set `true`.
   Users' passwords are wiped upon account deactivation, hence the need to set a new one here.
 
   Note: a user cannot be erased with this API. For more details on
@@ -223,7 +224,7 @@ The following parameters should be set in the URL:
   **or** displaynames that contain this value.
 - `guests` - string representing a bool - Is optional and if `false` will **exclude** guest users.
   Defaults to `true` to include guest users. This parameter is not supported when MSC3861 is enabled. [See #15582](https://github.com/matrix-org/synapse/pull/15582)
-- `admins` - Optional flag to filter admins. If `true`, only admins are queried. If `false`, admins are excluded from 
+- `admins` - Optional flag to filter admins. If `true`, only admins are queried. If `false`, admins are excluded from
   the query. When the flag is absent (the default), **both** admins and non-admins are included in the search results.
 - `deactivated` - string representing a bool - Is optional and if `true` will **include** deactivated users.
   Defaults to `false` to exclude deactivated users.
@@ -272,7 +273,7 @@ The following fields are returned in the JSON response body:
   - `is_guest` - bool - Status if that user is a guest account.
   - `admin` - bool - Status if that user is a server administrator.
   - `user_type` - string - Type of the user. Normal users are type `None`.
-    This allows user type specific behaviour. There are also types `support` and `bot`. 
+    This allows user type specific behaviour. There are also types `support` and `bot`.
   - `deactivated` - bool - Status if that user has been marked as deactivated.
   - `erased` - bool - Status if that user has been marked as erased.
   - `shadow_banned` - bool - Status if that user has been marked as shadow banned.
@@ -887,7 +888,7 @@ The following fields are returned in the JSON response body:
 
 ### Create a device
 
-Creates a new device for a specific `user_id` and `device_id`. Does nothing if the `device_id` 
+Creates a new device for a specific `user_id` and `device_id`. Does nothing if the `device_id`
 exists already.
 
 The API is:
@@ -1254,11 +1255,11 @@ The following parameters should be set in the URL:
 
 ## Check username availability
 
-Checks to see if a username is available, and valid, for the server. See [the client-server 
+Checks to see if a username is available, and valid, for the server. See [the client-server
 API](https://matrix.org/docs/spec/client_server/r0.6.0#get-matrix-client-r0-register-available)
 for more information.
 
-This endpoint will work even if registration is disabled on the server, unlike 
+This endpoint will work even if registration is disabled on the server, unlike
 `/_matrix/client/r0/register/available`.
 
 The API is: