[Security][Gap Fill][9.3 & Serverless]: Docs recent additions for gap fill feature (#4403)

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## Summary
Contributes to #3969 by
documenting the following UI changes that have been released in
Serverless:

- Updated panel about gaps info
- New gap fill status filter
- New gap fill status column in Rules table

Note that within the "Rule Monitoring" section, content about rule gaps
has been moved under a new sub-section titled "[Find rule execution
gaps](https://docs-v3-preview.elastic.dev/elastic/docs-content/pull/4403/solutions/security/detect-and-alert/monitor-rule-executions#rule-monitoring-tab-gaps)"
and the information has been slightly re-organized to show when certain
functionality is available.

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---------

Co-authored-by: Benjamin Ironside Goldstein <91905639+benironside@users.noreply.github.com>

Author: nastasha-solomon

solutions/images/security-monitor-table.png

@@ -37,26 +37,50 @@ On the **Rule Monitoring** tab, you can [sort and filter rules](../detect-and-al
 To sort the rules list, click any column header. To sort in descending order, click the column header again.
 ::::
 
-
 For detailed information on a rule, the alerts it generated, and associated errors, click on its name in the table. This also allows you to perform the same actions that are available on the [**Installed Rules** tab](manage-detection-rules.md), such as modifying or deleting rules, activating or deactivating rules, exporting or importing rules, and duplicating prebuilt rules.
 
-For information about rule execution gaps (which are periods of time when a rule didn't run), use the panel above the table. The panel contains the following:
+### Find rule execution gaps [rule-monitoring-tab-gaps]
 
-* **Time filter**: Allows you to select a time range for viewing gap data. 
-* **Total rules with gaps:** Provides metrics for rules with gaps:
-  
-  * {applies_to}`stack: ga 9.0` Tells you how many rules have unfilled or partially filled gaps within the selected time range. 
-  * {applies_to}`stack: ga 9.1` Tells you the number of rules with unfilled gaps (left metric) and the number of rules with gaps being filled (right metric). 
-  
-* {applies_to}`stack: ga 9.0` **Only rules with gaps**: Filters the Rules table to only display rules with unfilled or partially filled gaps.
-* {applies_to}`stack: ga 9.1` **Only rules with unfilled gaps**: Filters the Rules table to only display rules with unfilled gaps. Note that the filter excludes rules with gaps that are being filled. 
+The **Rule Monitoring** tab provides a starting point for understanding and remediating gaps in rule executions, which are periods of time where a rule didn’t run. Gaps can be caused by various disruptions, including system updates or simply turning off a rule. Addressing gaps is essential for maintaining consistent coverage and avoiding missed alerts.
 
-Within the Rules table, the **Last Gap (if any)** column conveys how long the most recent gap for a rule lasted. The **Unfilled gaps duration** column shows whether a rule still has gaps and provides a total sum of the remaining unfilled or partially filled gaps. The total sum can change based on the time range that you select in the panel above the table. If a rule has no gaps, the columns display a dash (`––`). 
+From the **Rule Monitoring** tab, you can get an overview of existing gaps and their status. The total number of rules with gaps is tracked in the panel above the Rules table. The information and functionality in the panel depends on the version of {{elastic-sec}} that you're using.
+
+::::{applies-switch}
+
+:::{applies-item} { "stack": "ga 9.3", "serverless": "ga" }
+The panel has the following:
+* **Rules with gaps:** Tells you the number of rules with gaps (left metric) and the number of rules with all gaps being filled (right metric). The metric shows data from the last 90 days.
+:::
+
+:::{applies-item} { "stack": "ga 9.1" }
+The panel has the following:
+* **Time filter**: Allows you to select a time range for viewing gap data.
+* **Total rules with gaps:** Tells you the number of rules with unfilled gaps (left metric) and the number of rules with gaps being filled (right metric) within the selected time range.
+* **Only rules with unfilled gaps**: Filters the Rules table to only display rules with unfilled gaps. Note that the filter excludes rules with gaps that are being filled.
+:::
+
+:::{applies-item} { "stack": "ga 9.0" }
+The panel has the following:
+* **Time filter**: Allows you to select a time range for viewing gap data.
+* **Total rules with gaps:** Tells you how many rules have unfilled or partially filled gaps within the selected time range.
+* **Only rules with gaps**: Filters the Rules table to only display rules with unfilled or partially filled gaps.
+:::
 
-::::{tip}
-For a detailed view of a rule's gaps, go to the **Execution results** tab and check the [Gaps table](/solutions/security/detect-and-alert/monitor-rule-executions.md#gaps-table).
 ::::
 
+Within the Rules table, several columns provide additional gap data:
+
+* **Last Gap (if any)**: Shows how long the most recent gap for a particular rule lasted.
+* **Unfilled gaps duration**: Shows whether a rule still has gaps and provides a total sum of the remaining unfilled or partially filled gaps. The total sum can change based on the time range that you select during the past 90 days (data on gaps that occurred past the last 90 days is not retained). If a rule has no gaps, the columns display a dash (`––`). 
+* {applies_to}`stack: ga 9.3`{applies_to}`serverless: ga`**Gap fill status**: Shows the status of the rule's gaps. If any gaps are unfilled, the gap status is `Unfilled`. If any gaps are being are being filled, the status is `In progress`. If all gaps are filled, the status is `Filled`. 
+
+    ::::{tip}
+    :applies_to:{stack: ga 9.3, serverless: ga}
+    Use the **Gap fill status** filter in the Rules table to find rules with the specified gap status. 
+    ::::
+
+To fill gaps for multiple rules, use the [**Fill gaps** bulk action](/solutions/security/detect-and-alert/manage-detection-rules.md#bulk-fill-gaps-multiple-rules) from the Rule's table. For a more detailed view of a rule's gaps, click the rule name to open its details, then go to the [Gaps table](/solutions/security/detect-and-alert/monitor-rule-executions.md#gaps-table) on the rule's **Execution results** tab. 
+
 ## Execution results tab [rule-execution-logs]
 
 From the **Execution results** tab, you can access the rule’s execution log, monitor and address gaps in a rule's execution schedule, and check manual runs for the rule. To find the tab, click the rule's name to open its details, then scroll down.
@@ -97,18 +121,14 @@ Use these controls to filter what’s included in the logs table:
    stack: preview 9.0, ga 9.1
 ```
 
-Gaps in rule executions are periods of time where a rule didn’t run. They can be caused by various disruptions, including system updates, rule failures, or simply turning off a rule. Addressing gaps is essential for maintaining consistent coverage and avoiding missed alerts.
+Use the information in the Gaps table to assess the scope and severity of rule execution gaps. To control what's shown in the table, you can filter the table by gap status, select a time range for viewing gap data, and sort multiple columns. 
+
+{applies_to}`stack: ga 9.3` Fill all gaps for the rule by clicking **Fill all gaps**.
 
 ::::{tip}
 Refer to the [Troubleshoot gaps](../../../troubleshoot/security/detection-rules.md#troubleshoot-gaps) section for strategies for avoiding gaps.
 ::::
 
-Use the information in the Gaps table to assess the scope and severity of rule execution gaps. To control what's shown in the table, you can filter the table by gap status, select a time range for viewing gap data, and sort multiple columns. In {{stack}} 9.1 and Serverless, fill all gaps for the current rule by clicking **Fill all gaps** in the Gaps table. 
-
-::::{note}
-{applies_to}`stack: ga 9.1` From the Rules table, fill gaps for multiple rules with the [**Fill gaps** bulk action](/solutions/security/detect-and-alert/manage-detection-rules.md#bulk-fill-gaps-multiple-rules).
-::::
-
 :::{image} /solutions/images/security-gaps-table.png
 :alt: Gaps table on the rule execution results tab
 :screenshot: