[Bug]: IPv4 Subnet Calculator and /31s

[ThrustVector]

Bug Type

Tool gives incorrect output

Expected output, actual output, steps to recreate

I know /31s are a bit of a special corner case but they are fairly widely used as p2p links in large Metro / WAN / ISP networks etc.

Enting a /31 reports 1 network address and 1 broadcast instead of 2 usable host (and no network/broadcast).
It also reports 0% Address Utilization.

Additional Info

No response

Checklist

• I have searched existing issues to make sure this bug hasn't been reported before
• I agree to follow the Code of Conduct

[Lissy93]

Done in #33 :)
Should be released shortly when v 1.6.0 comes out.