Document "*-transition" properties

[jfirebaugh]

Document how *-transition properties work.

[lucaswoj]

Both gl-js and gl-native support setting paint-property specific transition options. For example,the circle-radius transition may be controlled by setting the property circle-radius-transition. This should be clearly documented.

cc @danswick

[lucaswoj]

I just identified a minor outstanding bug related to this mapbox/mapbox-gl-js#1996

[peterqliu]

I'm interested in working on this, as it's required for setting transition durations at runtime with .setPaintProperty. Is there some way we can generate these (very repetitive) entries in an automated fashion, or are we stuck writing these manually?

[lucaswoj]

@peterqliu I think we can document this feature with a paragraph and some examples in the in the "Transition" section. Reading an entry per paint property would be as repetitive as writing them!

[mollymerp]

This is an easy fix and something we should hit asap. @peterqliu do you want to knock this out ? Happy to jump in if not.

[lbud]

Came up again in mapbox/mapbox-gl-js#4045

[lucaswoj]

This issue was moved to mapbox/mapbox-gl-js#4081