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

Roller-URL: https://ci.chromium.org/b/8748329252230670641
CQ-Do-Not-Cancel-Tryjobs: true
Original-Reviewed-on: https://fuchsia-review.googlesource.com/c/fuchsia/+/1046452
Original-Revision: 49911d2146c128397ca3a4d9f240ce7a309e82aa
GitOrigin-RevId: 2b7c58b3383186a9ec2e63c8932897dfee08be04
Change-Id: I32d02bae2e138ac8a5559cbe25e3e1f7d9a8c2b2
diff --git a/stem b/stem
index 96cff22..bb43c41 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="82290a5b35395ba067a6a5fed8eeab00e61fb6cc"/>
+             revision="49911d2146c128397ca3a4d9f240ce7a309e82aa"/>
   </projects>
   <hooks>
     <hook name="install-environment"