[whatwg] RFC 2732 reference unneeded

[Geoffrey Sneddon]

#terminology:
> For readability, the term URI is used to refer to both ASCII URIs  
> and Unicode IRIs, as those terms are defined by RFC 3986 and RFC  
> 3987 respectively, and as modified by RFC 2732.
>

RFC 2732 is irrelevant, as URIs as of RFC 3986 and IRIs as of RFC  
3987 define how to deal with IPv6 addresses. RFC 2732 is noted as  
obsoleted by RFC 3986.


- Geoffrey Sneddon