Add release notes for 8.10.0 (#7960)

Author: flobernd

docs/release-notes/release-notes-8.10.0.asciidoc

@@ -0,0 +1,13 @@
+[[release-notes-8.10.0]]
+== Release notes v8.10.0
+
+[discrete]
+=== Features & Enhancements
+
+- https://github.com/elastic/elasticsearch-net/pull/7931[#7931] Refactor OpenTelemetry implementation with updated Transport (issue: https://github.com/elastic/elasticsearch-net/issues/7885[#7885])
+- https://github.com/elastic/elasticsearch-net/pull/7953[#7953] Add `TDigestPercentilesAggregate` (issues: https://github.com/elastic/elasticsearch-net/issues/7923[#7923], https://github.com/elastic/elasticsearch-net/issues/7879[#7879])
+
+[discrete]
+=== Bug fixes
+
+- https://github.com/elastic/elasticsearch-net/pull/7956[#7956] Add `Similarity` to `KnnQuery` (issue: https://github.com/elastic/elasticsearch-net/issues/7952[#7952])

docs/release-notes/release-notes.asciidoc

@@ -3,6 +3,11 @@
 
 * <<breaking-changes-policy,Breaking changes policy>>
 
+[discrete]
+== Version 8.10
+
+* <<release-notes-8.10.0,Release notes v8.10.0>>
+
 [discrete]
 == Version 8.9