Warn about wrong separator of addr:housenumber values

[skyper]

I often find a comma being used as separator in addr:housenumber value instead of a semi-colon.

I know, that it might be tricky to define a list of allowed values. As far as I know, commas do not fit here.

[Don-vip]

People are following the wiki, we can't blame them:

• ​http://wiki.openstreetmap.org/wiki/Addresses#Buildings_with_multiple_house_numbers
• ​http://taginfo.openstreetmap.org/keys/addr%3Ahousenumber#wiki

=> The wiki must be updated and it must be discussed on @tagging before we implement this warning. I agree it should be a semi-colon like other tags.

[skyper]

See ​discussion on tagging@.