[ML] Force time shift documentation (#111668)

Co-authored-by: István Zoltán Szabó <istvan.szabo@elastic.co>

docs/reference/ml/anomaly-detection/apis/put-job.asciidoc

@@ -105,6 +105,20 @@ include::{es-ref-dir}/ml/ml-shared.asciidoc[tag=custom-rules]
 (array)
 include::{es-ref-dir}/ml/ml-shared.asciidoc[tag=custom-rules-actions]
 
+//Begin analysis_config.detectors.custom_rules.params
+`params`:::
+(object)
+include::{es-ref-dir}/ml/ml-shared.asciidoc[tag=custom-rules-params]
++
+.Properties of `params`
+[%collapsible%open]
+=======
+`force_time_shift`::::
+(object)
+include::{es-ref-dir}/ml/ml-shared.asciidoc[tag=custom-rules-params-force-time-shift]
+=======
+//End analysis_config.detectors.custom_rules.params
+
 //Begin analysis_config.detectors.custom_rules.conditions
 `conditions`:::
 (array)

docs/reference/ml/anomaly-detection/apis/update-job.asciidoc

@@ -111,6 +111,21 @@ include::{es-ref-dir}/ml/ml-shared.asciidoc[tag=custom-rules]
 (array)
 include::{es-ref-dir}/ml/ml-shared.asciidoc[tag=custom-rules-actions]
 
+//Begin analysis_config.detectors.custom_rules.params
+`params`:::
+(object)
+include::{es-ref-dir}/ml/ml-shared.asciidoc[tag=custom-rules-params]
++
+.Properties of `params`
+[%collapsible%open]
+=======
+[[force-time-shift-params]]
+`force_time_shift`::::
+(object)
+include::{es-ref-dir}/ml/ml-shared.asciidoc[tag=custom-rules-params-force-time-shift]
+=======
+//End analysis_config.detectors.custom_rules.params
+
 // Begin detectors.custom_rules.conditions
 `conditions`:::
 (array)

docs/reference/ml/ml-shared.asciidoc

@@ -384,6 +384,10 @@ model. Unless you also specify `skip_result`, the results will be created as
 usual. This action is suitable when certain values are expected to be
 consistently anomalous and they affect the model in a way that negatively
 impacts the rest of the results.
+* `force_time_shift`: This action will shift the time inside the anomaly detector by a specified
+amount. This is useful, e.g. to quickly adapt to the daylight saving time events that
+are known beforehand. This action requires a `force_time_shift` parameter
+in the `params` object.
 end::custom-rules-actions[]
 
 tag::custom-rules-scope[]
@@ -428,6 +432,16 @@ tag::custom-rules-conditions-value[]
 The value that is compared against the `applies_to` field using the `operator`.
 end::custom-rules-conditions-value[]
 
+tag::custom-rules-params[]
+A set of parameter objects that customize the actions defined in the custom rules
+actions array. The available parameters (depending on the specified actions) include:
+`force_time_shift`.
+end::custom-rules-params[]
+
+tag::custom-rules-params-force-time-shift[]
+Set `time_shift_amount` to the signed number of seconds by which you want to shift the time.
+end::custom-rules-params-force-time-shift[]
+
 tag::custom-settings[]
 Advanced configuration option. Contains custom metadata about the job. For
 example, it can contain custom URL information as shown in