Added mention about local doc

Author: mnocon

docs/api/rest_api/rest_api_usage/rest_api_usage.md

@@ -15,14 +15,18 @@ The REST API uses HTTP methods (such as `GET` and `PUBLISH`), and HTTP headers t
 
 The REST API is built on top of [API Platform](https://api-platform.com/docs/symfony/) and meets the [OpenAPI](https://www.openapis.org/) standard.
 
-You can downlaod the OpenAPI specification from the [REST API Reference](/api/rest_api/rest_api_reference/rest_api_reference.html), or generate it for your project by running one of the command below:
+You can download the OpenAPI specification from the [REST API Reference](/api/rest_api/rest_api_reference/rest_api_reference.html), or generate it for your project by running one of the commands below: 
 
 ``` bash
-php bin/console ibexa:openapi --output=spec.json # JSON output
-php bin/console ibexa:openapi --yaml --output=spec.yaml # YAML output
+php bin/console ibexa:openapi --output=openapi.json # JSON output
+php bin/console ibexa:openapi --yaml --output=openapi.yaml # YAML output
 ```
 
-With the specification file you can use the [available OpenAPI tools](https://tools.openapis.org/) to work faster with the API, for example, by generating libraries and clients for the API.
+Use the specification file with [available OpenAPI tools](https://tools.openapis.org/) to work faster with the API, for example, by generating libraries and clients for the API.
+
+!!! info
+
+    In [Symfony's `dev` environment](environments.md), you can access a REST API reference generated for your project by visiting the `/api/ibexa/v2/doc` route in the browser.
 
 ## URIs