Use named fields in `html.Attribute`
Use named fields in `html.Attribute`

Go's `go vet` has gotten a little more finnicky in 1.7 and now fails on
this. Tighten it up.


Former-commit-id: 3b605b71a5bf343570e6e27b7deba8b5b6ae10ee
brandur/sorg,brandur/sorg,brandur/sorg,brandur/sorg,brandur/sorg