[6.2] Fix a crash if we had a dollar identifier as the second parameter label in a closure not followed by a colon#3108

hamishknight merged 1 commit intoswiftlang:release/6.2swiftlang/swift-syntax:release/6.2from

hamishknight:3104-6.2hamishknight/swift-syntax:3104-6.2Copy head branch name to clipboard