Rework detections section

docs/getting-started/detections-req.asciidoc

@@ -45,7 +45,6 @@ these privileges must visit (click on) the *Detections* page:
 * The `manage` cluster privilege.
 * {kib} space `All` privileges for the `Security` feature (see
 {kibana-ref}/xpack-spaces.html#spaces-control-user-access[Feature access based on user privileges]).
-* The `maintenance` permission for `.siem-signals-<kib-space>`.
 * The `manage`, `write`,`read`, and `view_index_metadata` index privileges for all of these system indices:
 ** `.lists-<kib-space>`
 ** `.items-<kib-space>`
@@ -77,21 +76,29 @@ image::images/sec-admin-user.png[]
 After enabling Detections, only users with these permission can view and use the
 *Detections* page:
 
-* {kib} space `All` privileges for the `Security`  and `Saved Objects
-Management` features.
+**All**
+
+These permissions are required for both rule and alert management:
+
 * The `maintenance` permission for `.siem-signals-<kib-space>`.
 * The `read`, `write`, and `view_index_metadata` index privileges for all of these system indices:
 ** `.lists-<kib-space>`
 ** `.items-<kib-space>`
 +
 Where `<kib-space>` is the {kib} space name.
 
-Here's a screenshot of a user role that can view and create detection rules in all {kib}
-spaces:
-
 [role="screenshot"]
 image::images/sec-user.png[]
 
+**Rule**
+
+For rule management, make sure {kib} space with `All` privileges enabled for both `Security` and `Saved Objects Management` features.
+
+**Alert**
+
+If you only want a user to be update the status of alerts but not rule, only {kib} space with `All` privileges enabled for `Security` is required.
+
+
 [discrete]
 [[adv-list-settings]]
 == Configure list upload limits