[Swiftify] Fix return value transformation being applied last

Casting the return value to Span must be done outside
withUnsafeBufferPointer, to prevent returning a ~Escapable type from a
function without lifetime info. To do this we sort the transformations
so that the return value transformation is performed last. There was
a bug in the comparison, so the sorting was not always done correctly.

rdar://147934170

lib/Macros/Sources/SwiftMacros/SwiftifyImportMacro.swift

@@ -1142,7 +1142,13 @@ public struct SwiftifyImportMacro: PeerMacro {
       parsedArgs.sort { a, b in
         // make sure return value cast to Span happens last so that withUnsafeBufferPointer
         // doesn't return a ~Escapable type
-        (a.pointerIndex != .return && b.pointerIndex == .return) || paramOrReturnIndex(a.pointerIndex) < paramOrReturnIndex(b.pointerIndex)
+        if a.pointerIndex != .return && b.pointerIndex == .return {
+          return true
+        }
+        if a.pointerIndex == .return && b.pointerIndex != .return {
+          return false
+        }
+        return paramOrReturnIndex(a.pointerIndex) < paramOrReturnIndex(b.pointerIndex)
       }
       let baseBuilder = FunctionCallBuilder(funcDecl)