[Tagging] Remove non-prefixed versions of 'contact:' scheme

[Marc M.]

Hello,

Le 04.05.20 à 14:48, Paul Allen a écrit :
> I haven't seen them.

the two reasons are:

- avoid having 2 tags for the same thing.
it's bad for both contributors and data-uses.

- using namespace for contact: (like we do with addr:) it's useful for
the use of the data (you can group them without having to hard-code
all the possible variants that may exist in the world).
it's obviously also useful for an editor (it could display a preset
listing all the contact keys:* without having to hard-code them in
the preset).

Regards,
Marc