[docs] Add docs for `$TupleMap<T, F>` utility type
[docs] Add docs for `$TupleMap<T, F>` utility type

Summary: Adds docs for `TupleMap<T, F>` utility type

Reviewed By: calebmer

Differential Revision: D6336085

fbshipit-source-id: 5857b8ebc55f22d080e4838423b39083350033bf

gabelevi/flow,samwgoldman/flow,mroch/flow,JonathanUsername/flow,jamesgpearce/flow,jamesgpearce/flow,TiddoLangerak/flow,AgentME/flow,mroch/flow,JonathanUsername/flow,facebook/flow,popham/flow,jamesgpearce/flow,samwgoldman/flow,JonathanUsername/flow,mroch/flow,popham/flow,jamesgpearce/flow,nmote/flow,gabelevi/flow,samwgoldman/flow,claudiopro/flow,popham/flow,gabelevi/flow,gabelevi/flow,ylu1317/flow,popham/flow,ylu1317/flow,popham/flow,jamesgpearce/flow,nmote/flow,mroch/flow,facebook/flow,TiddoLangerak/flow,ylu1317/flow,nmote/flow,ylu1317/flow,JonathanUsername/flow,gabelevi/flow,JonathanUsername/flow,mroch/flow,jamesgpearce/flow,TiddoLangerak/flow,mroch/flow,facebook/flow,facebook/flow,AgentME/flow,popham/flow,claudiopro/flow,samwgoldman/flow,samwgoldman/flow,claudiopro/flow,facebook/flow,jamesgpearce/flow,TiddoLangerak/flow,facebook/flow,samwgoldman/flow,TiddoLangerak/flow,nmote/flow,gabelevi/flow,claudiopro/flow,JonathanUsername/flow,popham/flow,AgentME/flow,nmote/flow,JonathanUsername/flow,facebook/flow,claudiopro/flow,nmote/flow,AgentME/flow,samwgoldman/flow,nmote/flow,mroch/flow,AgentME/flow,gabelevi/flow,ylu1317/flow