+=(_:_:) Declarationstatic func += (lhs: inout String, rhs: String) See AlsoAppending Strings and Charactersappend(_:)append(_:)append(contentsOf:)append(contentsOf:)append(contentsOf:)append(contentsOf:)reserveCapacity(_:)+(_:_:)+(_:_:)+(_:_:)+(_:_:)+=(_:_:)