[Accepted] SE-0228: Fix Expressible By String Interpolation

Hello Swift Community,

The review for SE-0228 Fix ExpressibleByStringInterpolation ran from September 10...18, 2018. Feedback was overwhelmingly positive, and the proposal is accepted with one small amendment to provide a default implementation of init(stringLiteral:) for types that conform to ExpressibleByStringInterpolation.

Thank you to the authors and everyone who participated in the discussion!