chore: update API docs of Router (#1105)

### Description

- Update API docs of Router

### Issues

- Closes: #1098

---------

Co-authored-by: Vlada Dusek <[email protected]>

Author: Mantisus

Diff for: src/crawlee/router.py

@@ -14,7 +14,43 @@
 
 @docs_group('Classes')
 class Router(Generic[TCrawlingContext]):
-    """Dispatches requests to registered handlers based on their labels."""
+    """A request dispatching system that routes requests to registered handlers based on their labels.
+
+    The `Router` allows you to define and register request handlers for specific labels. When a request is received,
+    the router invokes the corresponding `request_handler` based on the request's `label`. If no matching handler
+    is found, the default handler is used.
+
+    ### Usage
+
+    ```python
+    from crawlee.crawlers import HttpCrawler, HttpCrawlingContext
+    from crawlee.router import Router
+
+    router = Router[HttpCrawlingContext]()
+
+
+    # Handler for requests without a matching label handler
+    @router.default_handler
+    async def default_handler(context: HttpCrawlingContext) -> None:
+        context.log.info(f'Request without label {context.request.url} ...')
+
+
+    # Handler for category requests
+    @router.handler(label='category')
+    async def category_handler(context: HttpCrawlingContext) -> None:
+        context.log.info(f'Category request {context.request.url} ...')
+
+
+    # Handler for product requests
+    @router.handler(label='product')
+    async def product_handler(context: HttpCrawlingContext) -> None:
+        context.log.info(f'Product {context.request.url} ...')
+
+
+    async def main() -> None:
+        crawler = HttpCrawler(request_handler=router)
+        await crawler.run()
+    """
 
     def __init__(self) -> None:
         self._default_handler: RequestHandler[TCrawlingContext] | None = None