doc: Fix typo

Author: franky47

packages/docs/content/docs/testing.mdx

@@ -100,7 +100,7 @@ This is extracted from the [Jest ESM guide](https://jestjs.io/docs/ecmascript-mo
 
 1. Add the following options to your jest.config.ts file:
 
-```ts title="jest.configx.ts"
+```ts title="jest.config.ts"
 const config: Config = {
   // <Other options here>
   // [!code highlight:3]