Update release notes to include 8.7.0 (#94934)

* Update release notes to include 8.7.0

Release notes and migration guide from 8.7.0 release ported into main
as well as re-generating 8.8.0 release notes. This latter step will
be overwritten anyway, multiple times, by more up-to-date regeneration
of the 8.8.0 release notes during the release process.

* Remove coming 8.7.0 line

* Update docs/reference/migration/migrate_8_7.asciidoc

Co-authored-by: Abdon Pijpelink <[email protected]>

* Make same change to 8.8

---------

Co-authored-by: Abdon Pijpelink <[email protected]>

Author: craigtaverner

docs/reference/migration/migrate_8_7.asciidoc

@@ -9,14 +9,37 @@ your application to {es} 8.7.
 
 See also <<release-highlights>> and <<es-release-notes>>.
 
-coming::[8.7.0]
-
-
 [discrete]
 [[breaking-changes-8.7]]
 === Breaking changes
 
+The following changes in {es} 8.7 might affect your applications
+and prevent them from operating normally.
+Before upgrading to 8.7, review these changes and take the described steps
+to mitigate the impact.
+
 // tag::notable-breaking-changes[]
-There are no breaking changes in {es} 8.7.
+There are no notable breaking changes in {es} 8.7.
 // end::notable-breaking-changes[]
+But there are some less critical breaking changes.
+
+[discrete]
+[[breaking_87_ingest_changes]]
+==== Ingest changes
+
+[[making_jsonprocessor_stricter_so_it_does_not_silently_drop_data]]
+.Making `JsonProcessor` stricter so that it does not silently drop data
+[%collapsible]
+====
+*Details* +
+The ingest node's `json` processor was previously lenient. It would accept invalid JSON data if it started with valid JSON data.
+Anything after the valid part would be silently discarded. From 8.7 onwards, the default behavior is to reject invalid JSON data with
+an exception so that data is not silently lost. The old behavior can be reproduced by passing `false` as the value of the new
+`strict_json_parsing` processor parameter.
+We consider this change to be a bugfix but list it here as a breaking change since it may affect the behavior of applications which
+were sending invalid JSON data to the `json` processor.
 
+*Impact* +
+Ensure your application only sends valid JSON data to the `json` processor, or modify the `json` processors in your pipelines to set
+the `strict_json_parsing` parameter to `false`.
+====

docs/reference/migration/migrate_8_8.asciidoc

@@ -20,6 +20,7 @@ coming::[8.8.0]
 There are no breaking changes in {es} 8.8.
 // end::notable-breaking-changes[]
 
+
 [discrete]
 [[deprecated-8.8]]
 === Deprecations
@@ -33,16 +34,17 @@ after upgrading to 8.8.
 To find out if you are using any deprecated functionality,
 enable <<deprecation-logging, deprecation logging>>.
 
+
 [discrete]
-[[deprecations_88_allocation]]
-==== Allocation deprecations
+[[deprecations_88_cluster_and_node_setting]]
+==== Cluster and node setting deprecations
 
-[[deprecate_allocation_choice]]
-.Deprecate `cluster.routing.allocation.type` setting
+[[deprecate_cluster_routing_allocation_type]]
+.Deprecate `cluster.routing.allocation.type`
 [%collapsible]
 ====
 *Details* +
-The `cluster.routing.allocation.type` setting is deprecated and will be removed in a future release of {es}.
+The `cluster.routing.allocation.type` setting is deprecated and will be removed in a future version.
 
 *Impact* +
 Discontinue use of the `cluster.routing.allocation.type` setting.