Unclear if From<Ipv4Addr> for u32 is network order or not

[nagisa]

The conversion traits are implemented for conversion between u32 and Ipv4Addr, but it is not clear what byte order is used.

[sfackler]

It is network order, but that should be documented on the impl.

[steveklabnik]

doc team triage: this would make a great first PR. I am happy to mentor anyone who wants to tackle this issue.

@steveklabnik I'd like to, is someone else working on this?

[steveklabnik]

@z1mvader nope, please do! Ping me if you need any help 😄