gopls/doc/release: include server side file watching in release note

For golang/go#67995

Change-Id: I07ba89eeb8d2e59b707b85cdd099548942e44e07
Reviewed-on: https://go-review.googlesource.com/c/tools/+/776881
Reviewed-by: Alan Donovan <adonovan@google.com>
Auto-Submit: Hongxiang Jiang <hxjiang@golang.org>
LUCI-TryBot-Result: golang-scoped@luci-project-accounts.iam.gserviceaccount.com <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
diff --git a/gopls/doc/release/v0.22.0.md b/gopls/doc/release/v0.22.0.md
index ae20a84..92d2627 100644
--- a/gopls/doc/release/v0.22.0.md
+++ b/gopls/doc/release/v0.22.0.md
@@ -119,3 +119,12 @@
 The `yield` analyzer, which detects problems in iterators that fail to
 stop once `yield()` returns false, has been rewritten as a non-sparse
 Killdall-style monotone dataflow analysis, improving its precision.
+
+## Server-side file watching
+
+Gopls introduces an experimental server-side file watching mechanism to monitor file system events directly. This feature supplements standard LSP file change notifications in environments or editor clients where client-side events may be unreliable or dropped.
+
+This feature is configured via the internal setting `fileWatcher`, which supports three strategies:
+- `"off"` (default): the client is solely responsible for change notification
+- `"poll"`: the server periodically scans workspace directories, using optimizations similar to `git status`
+- `"fsnotify"`: the server uses kernel support for file-change notification. This strategy is system dependent and may need to open many directories to watch a large workspace, risking [file descriptor exhaustion](https://github.com/fsnotify/fsnotify#kqueue-macos-all-bsd-systems)