lang/swift6: Add port: Powerful, flexible, multiplatform programming language (Version 6)
Swift is the only language that scales from embedded devices and
kernels to apps and cloud infrastructure. It's simple, and
expressive, with incredible performance and safety. And it has
unmatched interoperability with C and C++.
It's the combination of approachability, speed, safety, and all of
Swift's strengths that make it so unique.
PR: 296000
Differential Revision: https://reviews.freebsd.org/D57541