Update context documentation by removing broker examples

Removed broker examples for AIOKafka, Confluent, RabbitMQ, NATS, and Redis from the context documentation. Added information about setting a local context using the context manager.

Author: Lancetnik

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

@@ -90,64 +90,6 @@ context = ContextRepo({"secret_str": "my-perfect-secret"})
 app = FastStream(context=context)
 ```
 
-And in brokers:
-
-=== "AIOKafka"
-
-    ```python
-    from faststream.context import ContextRepo
-    from faststream.kafka import KafkaBroker
-
-    context = ContextRepo({"secret_str": "my-perfect-secret"})
-    broker = KafkaBroker(context=context)
-    ```
-
-=== "Confluent"
-
-    ```python
-    from faststream.context import ContextRepo
-    from faststream.confluent import KafkaBroker
-
-    context = ContextRepo({"secret_str": "my-perfect-secret"})
-    broker = KafkaBroker(context=context)
-    ```
-
-=== "RabbitMQ"
-
-    ```python
-    from faststream.context import ContextRepo
-    from faststream.rabbit import RabbitBroker
-
-    context = ContextRepo({"secret_str": "my-perfect-secret"})
-    broker = RabbitBroker(context=context)
-    ```
-
-=== "NATS"
-
-    ```python
-    from faststream.context import ContextRepo
-    from faststream.nats import NatsBroker
-
-    context = ContextRepo({"secret_str": "my-perfect-secret"})
-    broker = NatsBroker(context=context)
-    ```
-
-=== "Redis"
-
-    ```python
-    from faststream.context import ContextRepo
-    from faststream.redis import RedisBroker
-
-    context = ContextRepo({"secret_str": "my-perfect-secret"})
-    broker = RedisBroker(context=context)
-    ```
-
-To remove a field from the context use the `reset_global` method:
-
-```python
-context.reset_global("my_key")
-```
-
 !!! tip
     It is important to keep in mind that the broker context takes precedence over the FastStream context.
 
@@ -164,6 +106,12 @@ context.reset_global("my_key")
         assert data == "BROKER"
     ```
 
+To remove a field from the context use the `reset_global` method:
+
+```python
+context.reset_global("my_key")
+```
+
 ## Local
 
 To set a local context (available only within the message processing scope), use the context manager `scope`. It could me extremely uselful to fill context with additional options in [Middlewares](../middlewares/){.internal-link}