[roll] Roll fuchsia [docs][fid] Update bindings spec

This CL makes the following changes to the FIDL bindings spec:

* Update sections on flexible types and unknown data, based on
  "RFC-0137: Discard unknown data in FIDL".

* Update section on terminal errors to clarify that synchronous bindings
  are not required to close the channel (to avoid taking locks).

Original-Reviewed-on: https://fuchsia-review.googlesource.com/c/fuchsia/+/818609
Original-Revision: 1b02f5a84713560fc3a499186e2593a20ef9ce4b
GitOrigin-RevId: 6bbe4eca9ef34f15f511d83ae804a1579b11a32c
Change-Id: Ia2d7815c7e9e02f85b6ff5390f2a11812430d94c
diff --git a/stem b/stem
index fe4aaf8..0390aff 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="f87c77461da8f5fc53f1d88647388b07ddd6cd33"/>
+             revision="1b02f5a84713560fc3a499186e2593a20ef9ce4b"/>
   </projects>
   <hooks>
     <hook name="install-environment"