Docs: Migrating platform docs to /guide/platform/ with new landing page

Bug:29575457
Change-Id: I6d576e9dd28132fcf7e6e017187f30702066c2af
diff --git a/docs/html/_redirects.yaml b/docs/html/_redirects.yaml
index 8507128..89f43d8 100644
--- a/docs/html/_redirects.yaml
+++ b/docs/html/_redirects.yaml
@@ -1220,4 +1220,5 @@
   to: /guide/topics/ui/notifiers/notifications.html
 - from: /preview/features/multilingual-support.html
   to: /guide/topics/resources/multilingual-support.html
-
+- from: /preview/j8-jack.html
+  to: /guide/platform/j8-jack.html
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