Provide documentation for the WatchListClient feature

Author: p0lyn0mial

content/en/docs/reference/command-line-tools-reference/feature-gates/watch-list-client.md

@@ -0,0 +1,17 @@
+---
+title: WatchListClient
+content_type: feature_gate
+_build:
+  list: never
+  render: false
+
+stages:
+  - stage: beta
+    defaultValue: false
+    fromVersion: "1.30"
+---
+Allows an API client to request a stream of data rather than fetching a full list. 
+This functionality is available in `client-go` and requires the 
+[WatchList](/docs/reference/command-line-tools-reference/feature-gates/) 
+feature to be enabled on the server. 
+If the `WatchList` is not supported on the server, the client will seamlessly fall back to a standard list request.