doc: add missing metadata for fs.open

PR-URL: #19585
Refs: #18801
Reviewed-By: Vse Mozhet Byt <[email protected]>
Reviewed-By: Ruben Bridgewater <[email protected]>
Reviewed-By: Trivikram Kamat <[email protected]>

Author: tniessen

doc/api/fs.md

@@ -2076,6 +2076,9 @@ object with an `encoding` property specifying the character encoding to use.
 <!-- YAML
 added: v0.0.2
 changes:
+  - version: v9.9.0
+    pr-url: https://github.com/nodejs/node/pull/18801
+    description: The `as` and `as+` modes are supported now.
   - version: v7.6.0
     pr-url: https://github.com/nodejs/node/pull/10739
     description: The `path` parameter can be a WHATWG `URL` object using `file:`