[Tagging] Feature Proposal - RFC - Bench: replace seats by capacity

[martianfreeloader]

Sorry for double-posting.

It has been brought to my attention that I had accidentally written my 
original mail within an existing thread.

I hope, this one fixes it.

--------------------
Original mail:

For consistency's sake, I propose to stop using seats=* on benches. 
Instead, capacity=* should be used.

For details, see the proposal: 
https://wiki.openstreetmap.org/wiki/Proposed_features/Bench:_replace_seats_by_capacity

Please discuss this proposal on its Wiki Talk page.