fix link for api keys docs

ui/pages/ApiKeys.tsx

@@ -56,7 +56,7 @@ const ApiKeysPage: React.FC = () => {
   const description = (
     <AccountPageDescription>
       Create API keys to use for your RPC and EthRPC API requests. For more information, see { space }
-      <Link href="#">“How to use a Blockscout API key”</Link>.
+      <Link href="https://docs.blockscout.com/for-users/api#api-keys">“How to use a Blockscout API key”</Link>.
     </AccountPageDescription>
   );