[DOCS] Drafted 6.2.2 release notes
Original commit: elastic/x-pack-elasticsearch@89eff13bd74f3625c3e99373f6cd0ce0ea44047f
++++
To be determined...
+
+////
+[[xes-bug-6.2.2]]
+[float]
+=== Bug fixes
+////
+////
+Machine Learning::
+* [ML] Fix exception categorising an empty string
+//Repo: x-pack-elasticsearch
+//Pull: 3870
+////
+////
+Monitoring::
+* [Monitoring] Register affixed Header Setting
+// Repo: x-pack-elasticsearch
+// Pull: 3893
+////
+////
+Security::
+* Move CachingRealm interface to core for custom realm extensions
+// Repo: x-pack-elasticsearch
+// Pull: 3866
+* If the realm uses native role mappings and the security index health changes,
+the realm caches are cleared. For example, they are cleared when the index
+recovers from a red state, when the index is deleted, when the index becomes
+outdated, or when the index becomes up-to-date.
+// Repo: x-pack-elasticsearch
+// Pull: 3782
+* Fixed a bug that could prevent auditing to a remote index if the remote
+cluster was re-started at the same time as the audited cluster.
+// Repo: x-pack-elasticsearch
+// Pull: 3807
+* Remove Issuer/Serial from AKI in certutil/certgen
+//Repo: x-pack-elasticsearch
+// Pull: 3931
+////
+////
+Watcher::
+* Watcher: Fix proxy scheme to default to HTTP
+// Repo: x-pack-elasticsearch
+// Pull: 3844
+* Watcher: Register HTML sanitizer settings
+// Repo: x-pack-elasticsearch
+// Pull: 3904
+////
