The Cloud Router documentation now includes a page that describes the possible values for a BGP session's state

## Change The Cloud Router documentation now includes a [page](https://cloud.google.com/network-connectivity/docs/router/concepts/bgp-states) that describes the possible values for a BGP session's state. Also, the documentation about diagnostic messages and session states related to Bidirectional Forwarding Detection (BFD) has moved from [Troubleshooting](https://cloud.google.com/network-connectivity/docs/router/support/troubleshooting) to a [new page](https://cloud.google.com/network-connectivity/docs/router/concepts/bfd). BFD is in [preview](https://cloud.google.com/products#product-launch-stages) and is covered by the [Pre-GA Offerings Terms](https://cloud.google.com/terms/service-terms#1) of the Google Cloud Terms of Service.