[roll] Roll fuchsia [gndoc] Update GN build arguments documentation

Roller-URL: https://ci.chromium.org/b/8752225505724378433
CQ-Do-Not-Cancel-Tryjobs: true
Original-Reviewed-on: https://fuchsia-review.googlesource.com/c/fuchsia/+/1016737
Original-Revision: 7239cfb617f818bb357924cc2d3ef1876e27c8e9
GitOrigin-RevId: f0aaa84216985fb83e9d37d8c7fcaa25a895a145
Change-Id: Ic1038e414301607e9f6cc21b1372ce3acee17550
diff --git a/stem b/stem
index a509494..eb0f781 100644
--- a/stem
+++ b/stem
@@ -11,7 +11,7 @@
              githooks="integration/git-hooks"
              remote="https://fuchsia.googlesource.com/fuchsia"
              gerrithost="https://fuchsia-review.googlesource.com"
-             revision="96777e45877584f1b9cb22aacd37d8b8fb8a99cf"/>
+             revision="7239cfb617f818bb357924cc2d3ef1876e27c8e9"/>
   </projects>
   <hooks>
     <hook name="install-environment"