[roll] Roll fuchsia [multifuchsia] Print usage() upon incorrect number of args

Adds functionality for catching incorrect number of arguments to the
main multifuchsia script, and prints out a usage summary before exiting,
prompting the user to checkt the input args and correct them.

Original-Bug: b/368579535
Original-Reviewed-on: https://fuchsia-review.googlesource.com/c/fuchsia/+/1122793
Original-Revision: 7d4cc6d4c1aac5fa487e18c31eec115f412bd0a1
GitOrigin-RevId: 9a16f362d9a6be1cefed7cab458c3e7ff7e29dda
Change-Id: I38b510937fefdfe1c28653e9c72bfec547a843f8
diff --git a/stem b/stem
index ca258e6..94028fd 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="ae0f666955a52d2b59c0759fe09bb5a195599f54"/>
+             revision="7d4cc6d4c1aac5fa487e18c31eec115f412bd0a1"/>
   </projects>
   <hooks>
     <hook name="install-environment"