Add "Learn more" arrow to Retries with Backoff card (#359)

Author: devalog

fern/products/sdks/capabilities.mdx

@@ -40,6 +40,11 @@ layout: overview
   </Card>
   <Card title="Retries with Backoff" icon="fa-duotone fa-repeat" href="/sdks/deep-dives/retries-with-backoff">
     Automatically retry failed requests with exponential backoff
+    <p className="text-(color:--grayscale-a11) font-bold mt-2 flex items-center gap-1">
+      Learn more
+      <img src="./images/arrow-right-black.svg" alt="Arrow right light" className="arrow-right dark:hidden m-0 h-4 w-4" noZoom />
+      <img src="./images/arrow-right-white.svg" alt="Arrow right light" className="arrow-right hidden dark:block m-0 h-4 w-4" noZoom />
+    </p>
   </Card>
   <Card title="Webhook Signature Verification" icon="fa-duotone fa-key">
     Verify the signature of incoming webhook requests