Minor fixes in Futures.md (#911)
Minor fixes in Futures.md (#911)

Summary:
lvalue-qualified then() has been deprecated
lvalue-qualified get() has been deleted
Pull Request resolved: https://github.com/facebook/folly/pull/911

Reviewed By: LeeHowes

Differential Revision: D9310836

Pulled By: yfeldblum

fbshipit-source-id: 662596bf5985f7ceabb2a23725d51f8e05407340

facebook/folly,facebook/folly,facebook/folly,facebook/folly,facebook/folly