Add presets for riding arena (pitch + equestrian)

[Hufkratzer]

Please add presets for riding arenas tagged as leisure=pitch + sport=equestrian 🐴, taginfo = 15K.

Riding arenas are the areas where the horse riding (competitions, training, learning) actually takes place while a riding stable / facility (leisure=horse_riding, what you have rececently added, thanks) usually contains other areas, buildings and things as well. So riding stables mostly contain riding arenas, but not every riding arena is part of a riding stable (like not every soccer pitch is part of a sports centre).

Riding arenas may be covered / roofed / indoors, therefore please add the field "building".

A synoym (British English) is "riding school" (see wikipedia)

Icon

I think you can use the same horse riding icon as for the riding stables; like you also use the same icon for some kinds of pitches, sports centre and stadium. It may perhaps later be replaced by a more sporty looking version 🏇, but at least it shows a 🐴 and the most important thing is that someone who searches for "riding arena" (or synonyms) will find the presets with leisure=pitch + sport=equestrian.