fly_volume_size does not exist, official dashboard uses fly_instance_filesystem_blocks_

[supermar1010]

I found an issue with this document.

Title: Metrics on Fly.io
Location: https://fly.io/docs/monitoring/metrics/#volumes-fly_volume_
Source: https://github.com/superfly/docs/blob/main/monitoring/metrics.html.md

Describe the issue

The described property does not exist. The official dashboard uses fly_instance_filesystem_blocks_avail{mount!="/",mount!="/.fly-upper-layer"}