Update docs

Author: nick-benoit

docs/resources/kibana_security_detection_rule.md

@@ -215,19 +215,10 @@ Required:
 
 Optional:
 
-- `duration` (Attributes) Duration for which alerts are suppressed. (see [below for nested schema](#nestedatt--alert_suppression--duration))
+- `duration` (String) Duration for which alerts are suppressed.
 - `group_by` (List of String) Array of field names to group alerts by for suppression.
 - `missing_fields_strategy` (String) Strategy for handling missing fields in suppression grouping: 'suppress' - only one alert will be created per suppress by bucket, 'doNotSuppress' - per each document a separate alert will be created.
 
-<a id="nestedatt--alert_suppression--duration"></a>
-### Nested Schema for `alert_suppression.duration`
-
-Required:
-
-- `unit` (String) Duration unit (s, m, h).
-- `value` (Number) Duration value.
-
-
 
 <a id="nestedatt--exceptions_list"></a>
 ### Nested Schema for `exceptions_list`