[roll] Roll fuchsia [docs] Add GN import for fuchsia_unittest_package in Rust testing

Adds the missing import("//build/components.gni") statement to the documentation for packaging and running Rust tests. This is required to use the fuchsia_unittest_package template.

Original-Original-Fixed: 328619658

Test: None, documentation change.

TAG=agy

CONV=d5d98da5-866c-4e06-b361-32f5158ad746

Original-Original-Reviewed-on: https://fuchsia-review.googlesource.com/c/fuchsia/+/1666384
Original-Original-Revision: 63f9875cec4bf78d69d3410c3532c904fa442f49
GitOrigin-RevId: c537845a2f48df8e98e96b08514c9db8156f916f
Change-Id: I7a5bf4850ddf60009bf9ccb17eb273357a2c9d1d
Reviewed-on: https://fuchsia-review.googlesource.com/c/integration/+/1672234
Cr-Commit-Position: refs/heads/main@{#195261}

stem

diff --git a/stem b/stem
index 0c3a4e7..d6d00d7 100644
--- a/stem
+++ b/stem
@@ -8,6 +8,6 @@
             manifest="manifests/platform"
             root=""
             remote="https://fuchsia.googlesource.com/fuchsia"
-            revision="e0b4ed4efca6053898d057d79d59772f76d7c3a5"/>
+            revision="63f9875cec4bf78d69d3410c3532c904fa442f49"/>
   </imports>
 </manifest>