[DOCS] Adds deprecation details for max_page_search_size (#79664)

docs/reference/migration/migrate_7_8.asciidoc

@@ -211,4 +211,19 @@ Assign users with the `kibana_user` role to the `kibana_admin` role.
 Discontinue use of the `kibana_user` role.
 ====
 
+[discrete]
+[[breaking_78_transform_changes]]
+=== Transforms changes
+
+.The `max_page_search_size` property is deprecated in the `pivot` {transform} configuration object
+[%collapsible]
+====
+*Details* +
+The `max_page_search_size` property within `pivot` is deprecated in the
+<<put-transform,create {transform}>> and <<preview-transform,preview {transform}>>
+APIs.
+
+*Impact* +
+Use the `max_page_search_size` property within `settings` instead.
+====
 //end::notable-breaking-changes[]

docs/reference/transform/apis/preview-transform.asciidoc

@@ -130,6 +130,10 @@ include::{es-repo-dir}/rest-api/common-parms.asciidoc[tag=pivot-aggs]
 `group_by`:::
 (Required, object)
 include::{es-repo-dir}/rest-api/common-parms.asciidoc[tag=pivot-group-by]
+
+`max_page_search_size`:::
+(Optional, integer)
+deprecated:[7.8.0,Moved to `settings`.]
 ====
 //End pivot
 

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

@@ -149,6 +149,9 @@ include::{es-repo-dir}/rest-api/common-parms.asciidoc[tag=pivot-aggs]
 (Required, object)
 include::{es-repo-dir}/rest-api/common-parms.asciidoc[tag=pivot-group-by]
 
+`max_page_search_size`:::
+(Optional, integer)
+deprecated:[7.8.0,Moved to `settings`.]
 ====
 //End pivot
 

x-pack/plugin/core/src/main/java/org/elasticsearch/xpack/core/transform/TransformDeprecations.java

@@ -11,10 +11,6 @@ public class TransformDeprecations {
 
     public static final String UPGRADE_TRANSFORM_URL = "https://ela.st/es-7-upgrade-transforms";
 
-    // breaking changes base url for the _next_ major release
-    public static final String BREAKING_CHANGES_BASE_URL =
-        "https://www.elastic.co/guide/en/elasticsearch/reference/master/migrating-8.0.html";
-
     public static final String QUERY_BREAKING_CHANGES_URL = "https://ela.st/es-deprecation-8-transform-query-options";
 
     public static final String AGGS_BREAKING_CHANGES_URL = "https://ela.st/es-deprecation-8-transform-aggregation-options";
@@ -24,5 +20,6 @@ public class TransformDeprecations {
     public static final String ACTION_MAX_PAGE_SEARCH_SIZE_IS_DEPRECATED =
         "[max_page_search_size] is deprecated inside pivot. Use settings instead.";
 
+    public static final String MAX_PAGE_SEARCH_SIZE_BREAKING_CHANGES_URL = "https://ela.st/es-deprecation-7-transform-max-page-search-size";
     private TransformDeprecations() {}
 }

x-pack/plugin/core/src/main/java/org/elasticsearch/xpack/core/transform/transforms/pivot/PivotConfig.java

@@ -186,7 +186,7 @@ public class PivotConfig implements Writeable, ToXContentObject {
                 new DeprecationIssue(
                     Level.WARNING,
                     "Transform [" + id + "] uses deprecated max_page_search_size",
-                    TransformDeprecations.BREAKING_CHANGES_BASE_URL,
+                    TransformDeprecations.MAX_PAGE_SEARCH_SIZE_BREAKING_CHANGES_URL,
                     TransformDeprecations.ACTION_MAX_PAGE_SEARCH_SIZE_IS_DEPRECATED,
                     false,
                     null

x-pack/plugin/core/src/test/java/org/elasticsearch/xpack/core/transform/transforms/TransformConfigTests.java

@@ -750,7 +750,7 @@ public class TransformConfigTests extends AbstractSerializingTransformTestCase<T
                     new DeprecationIssue(
                         Level.WARNING,
                         "Transform [" + id + "] uses deprecated max_page_search_size",
-                        TransformDeprecations.BREAKING_CHANGES_BASE_URL,
+                        TransformDeprecations.MAX_PAGE_SEARCH_SIZE_BREAKING_CHANGES_URL,
                         TransformDeprecations.ACTION_MAX_PAGE_SEARCH_SIZE_IS_DEPRECATED,
                         false,
                         null
@@ -772,7 +772,7 @@ public class TransformConfigTests extends AbstractSerializingTransformTestCase<T
                     new DeprecationIssue(
                         Level.WARNING,
                         "Transform [" + id + "] uses deprecated max_page_search_size",
-                        TransformDeprecations.BREAKING_CHANGES_BASE_URL,
+                        TransformDeprecations.MAX_PAGE_SEARCH_SIZE_BREAKING_CHANGES_URL,
                         TransformDeprecations.ACTION_MAX_PAGE_SEARCH_SIZE_IS_DEPRECATED,
                         false,
                         null
@@ -802,7 +802,7 @@ public class TransformConfigTests extends AbstractSerializingTransformTestCase<T
                     new DeprecationIssue(
                         Level.WARNING,
                         "Transform [" + id + "] uses deprecated max_page_search_size",
-                        TransformDeprecations.BREAKING_CHANGES_BASE_URL,
+                        TransformDeprecations.MAX_PAGE_SEARCH_SIZE_BREAKING_CHANGES_URL,
                         TransformDeprecations.ACTION_MAX_PAGE_SEARCH_SIZE_IS_DEPRECATED,
                         false,
                         null