[#10459] 📝 Update documentation to use yarn --cwd arg

Signed-off-by: LvffY <louberger@hotmail.fr>

docs/integrations/aws-s3/discovery.md

@@ -29,9 +29,9 @@ Note the `s3-discovery` type, as this is not a regular `url` processor.
 
 As this processor is not one of the default providers, you will first need to install the AWS catalog plugin:
 
-```shell
-cd packages/backend
-yarn install @backstage/plugin-catalog-backend-module-aws
+```bash
+# From the Backstage root directory
+yarn install --cwd packages/backend @backstage/plugin-catalog-backend-module-aws
 ```
 
 Once you've done that, you'll also need to add the segment below to `packages/backend/src/plugins/catalog.ts`: