[Tagging] Distinction between amenity=restaurant and fast_food

[Richard Weait]

fast_food vs. restaurant, ah yes, a debate for the ages. :-)

I used the counter service versus table service distinction for a
while, then another mapper from our local group suggested that a
distinction with fewer exceptions is: pay before eating (fast_food)
vs. pay after eating (restaurant).

It isn't a perfect match, but it works pretty well here.

If I'm really having a hard time selecting the perfect tag from
equally good candidates, I'll check what other local mappers have used
and follow their guidance.