Follow-up on 6edb749534, where default
`autocomplete` values were introduced as default for password fields,
according to the new autofill specs.
This patch allows developers to force the "autocomplete" attribute value
on password fields, in case there really is a need for a value that is
not `new-password` (which BTW now triggers the password generator wizard
in many browsers).
It is useful for example when a backend form really needs to ask the
user for their current password, so the correct `autocomplete`
value is `current-password`, as on the login form.
Olivier Dony
61c21213b2