Refactor context example to include type annotations

Updated the context handling example to use type annotations.

Author: Lancetnik

docs/docs/en/getting-started/context.md

@@ -94,15 +94,15 @@ app = FastStream(context=context)
     It is important to keep in mind that the broker context takes precedence over the FastStream context.
 
     ```python
-    from faststream import FastStream
-    from faststream.context import ContextRepo
+    from typing import Annotated
+    from faststream import FastStream, ContextRepo, Context
     from faststream.nats import NatsBroker
 
     broker = NatsBroker(context=ContextRepo({"data": "BROKER"}))
     app = FastStream(broker, context=ContextRepo({"data": "APP"}))
 
     @broker.subscriber("queue")
-    async def handle(data = Context()) -> None:
+    async def handle(data: Annotated[str, Context()]) -> None:
         assert data == "BROKER"
     ```