[PR] [Docs] correct $Keys<T> documentation logged value
[PR] [Docs] correct $Keys<T> documentation logged value

Summary: Pull Request resolved: https://github.com/facebook/flow/pull/5756

Reviewed By: dsainati1

Differential Revision: D13979775

Pulled By: mvitousek

fbshipit-source-id: 387e7b8cc624c3496e7ff4c73ac6e7a59eea053c

facebook/flow,facebook/flow,popham/flow,gabelevi/flow,popham/flow,facebook/flow,samwgoldman/flow,samwgoldman/flow,samwgoldman/flow,mroch/flow,samwgoldman/flow,popham/flow,popham/flow,mroch/flow,gabelevi/flow,popham/flow,gabelevi/flow,samwgoldman/flow,gabelevi/flow,facebook/flow,facebook/flow,mroch/flow,mroch/flow,gabelevi/flow,mroch/flow,mroch/flow,samwgoldman/flow,facebook/flow,mroch/flow,gabelevi/flow,popham/flow,popham/flow,samwgoldman/flow,gabelevi/flow,facebook/flow