Update docs for v8.15.5 release (elastic#117402)

docs/reference/release-notes.asciidoc

@@ -6,6 +6,7 @@
 
 This section summarizes the changes in each release.
 
+* <<release-notes-8.15.5>>
 * <<release-notes-8.15.4>>
 * <<release-notes-8.15.3>>
 * <<release-notes-8.15.2>>
@@ -74,6 +75,7 @@ This section summarizes the changes in each release.
 
 --
 
+include::release-notes/8.15.5.asciidoc[]
 include::release-notes/8.15.4.asciidoc[]
 include::release-notes/8.15.3.asciidoc[]
 include::release-notes/8.15.2.asciidoc[]

docs/reference/release-notes/8.15.5.asciidoc

@@ -0,0 +1,31 @@
+[[release-notes-8.15.5]]
+== {es} version 8.15.5
+
+coming[8.15.5]
+
+Also see <<breaking-changes-8.15,Breaking changes in 8.15>>.
+
+[[bug-8.15.5]]
+[float]
+=== Bug fixes
+
+Machine Learning::
+* Fix bug in ML autoscaling when some node info is unavailable {es-pull}116650[#116650]
+
+Mapping::
+* Change synthetic source logic for `constant_keyword` {es-pull}117182[#117182] (issue: {es-issue}117083[#117083])
+
+Relevance::
+* Fix handling of bulk requests with semantic text fields and delete ops {es-pull}116942[#116942]
+
+Vector Search::
+* Update Semantic Query To Handle Zero Size Responses {es-pull}116277[#116277] (issue: {es-issue}116083[#116083])
+
+[[enhancement-8.15.5]]
+[float]
+=== Enhancements
+
+Data streams::
+* Apm-data: disable date_detection for all apm data streams {es-pull}116995[#116995]
+
+