Fix guides/backend/xata.mdx (withastro#11602)

Co-authored-by: jp-knj <[email protected]>
Co-authored-by: Yan <[email protected]>

Author: 3 people

src/content/docs/en/guides/backend/xata.mdx

@@ -19,7 +19,7 @@ import { FileTree } from '@astrojs/starlight/components';
 ### Prerequisites
 
 - A [Xata](https://app.xata.io/signin) account with a created database. (You can use the sample database from the Web UI.)
-- An Access Token (`XATA_TOKEN_API`).
+- An Access Token (`XATA_API_KEY`).
 - Your Database URL.
 
 After you update and initialize the [Xata CLI](https://xata.io/docs/getting-started/installation), you will have your API token in your `.env` file and database URL defined.