[Tagging] Documenting entrance=shop

[Tobias Knerr]

Am 05.06.22 um 10:13 schrieb Mateusz Konieczny via Tagging:
> https://wiki.openstreetmap.org/wiki/Tag:entrance%3Dshop 

I consider entrance=shop a bad idea because it leads to mixing different 
attributes in the same key. Specifically:

* Which kind of entrance is it? (main, service, ...)
* What is it an entrance _to_? (shop, home, ...)

It would be much saner to invent a second key for the "shop" value 
(entrance_to=shop).