[DOCS] Clarifies data frame transform frequency is also for retries (#44229)

In data frame transforms the same scheduler controls both
retries in the event of search failures and gaps between
checks for changes when the transform is running continuously.

Co-Authored-By: Lisa Cawley <lcawley@elastic.co>

docs/reference/data-frames/apis/put-transform.asciidoc

@@ -74,9 +74,11 @@ attempts the unauthorized operation. The default value is `false`.
     (Optional, string) The unique identifier for a <<pipeline,pipeline>>.
 
 `frequency`::
-  (Optional, time units) The interval between checks for changes in the source indices
-  when the {dataframe-transform} is running continuously. Defaults to `1m`.
-  The lowest permitted value is `1s`; the highest `1h`.
+  (Optional, time units) The interval between checks for changes in the source
+  indices when the {dataframe-transform} is running continuously. Also determines
+  the retry interval in the event of transient failures while the {dataframe-transform} is
+  searching or indexing. The minimum value is `1s` and the maximum is `1h`. The
+  default value is `1m`.
 
 `pivot`::
   (Required, object) Defines the pivot function `group by` fields and the aggregation to

docs/reference/data-frames/apis/transformresource.asciidoc

@@ -21,8 +21,10 @@ For more information, see
   
 `frequency`::
   (time units) The interval between checks for changes in the source indices
-  when the {dataframe-transform} is running continuously. The minimum value is
-  `1s` and the maximum is `1h`. The default value is `1m`.
+  when the {dataframe-transform} is running continuously. Also determines the
+  retry interval in the event of transient failures while the {dataframe-transform} is
+  searching or indexing. The minimum value is `1s` and the maximum is `1h`. The
+  default value is `1m`.
 
 `id`::
   (string) A unique identifier for the {dataframe-transform}.
@@ -122,4 +124,4 @@ composite aggregations. See
 ==== {api-examples-title}
 
 See the
-<<put-data-frame-transform-example,create {dataframe-transforms} API examples>>.
+<<put-data-frame-transform-example,create {dataframe-transforms} API examples>>.