Unresolved reference to xray.recorder.capture_async decorator

Hi,

Pycharm highlights **xray_recorder.capture_async** decorator as an unresolved reference (xray_recorder.capture works just fine) and indeed, the code is not working. According to the documentation, this is all the setup code required to make it work:

```
from aws_xray_sdk.core.async_context import AsyncContext
from aws_xray_sdk.core import xray_recorder

xray_recorder.configure(service='service_name', context=AsyncContext())
```
The same thing happens with async context manager.

So I'm wondering if the docs are up to date with the current release.

Also, I have these dependencies in my environment:
```
aiobotocore==1.4.2
boto3==1.18.37
boto3-stubs==1.20.46.post1
botocore==1.21.37
botocore-stubs==1.23.46.post1
aws-xray-sdk==2.9.0
```

Thank you