docs build fails in google-cloud-edgenetwork

[parthea]

See https://github.com/googleapis/googleapis/blob/492e772e24f4122600c0e106945075a8ff3f6255/google/cloud/edgenetwork/v1/resources.proto#L553-L555 where there a list without a list item separator.

The proto has

    // Time this session has been up.
    // Format:
    //  14 years, 51 weeks, 6 days, 23 hours, 59 minutes, 59 seconds

but sphinx expects a list item separator such as -. Another option is to remove the leading space in the list item.

This caused the docs build to fail with docstring of google.cloud.edgenetwork_v1.types.resources.RouterStatus.BgpPeerStatus:40:Block quote ends without a blank line; unexpected unindent.

Either of the following will solve the issue.

    // Time this session has been up.
    // Format:
    // 14 years, 51 weeks, 6 days, 23 hours, 59 minutes, 59 seconds

or

    // Time this session has been up.
    // Format:
    // - 14 years, 51 weeks, 6 days, 23 hours, 59 minutes, 59 seconds

We should update the AIPs to require a specific format for lists and add a linter rule to check the formatting via https://github.com/googleapis/api-linter .