Add review link to SE-0394

Author: beccadax

proposals/0394-swiftpm-expression-macros.md

@@ -5,7 +5,7 @@
 * Review Manager: [Becca Royal-Gordon](https://github.com/beccadax)
 * Status: **Active Review (April 3...April 17, 2023)**
 * Implementation: **Available behind pre-release tools-version** ([apple/swift-package-manager#6185](https://github.com/apple/swift-package-manager/pull/6185), [apple/swift-package-manager#6200](https://github.com/apple/swift-package-manager/pull/6200))
-* Review: ([pitch 1](https://forums.swift.org/t/pitch-package-manager-support-for-custom-macros/63482)) ([pitch 2](https://forums.swift.org/t/pitch-2-package-manager-support-for-custom-macros/63868))
+* Review: ([pitch 1](https://forums.swift.org/t/pitch-package-manager-support-for-custom-macros/63482)) ([pitch 2](https://forums.swift.org/t/pitch-2-package-manager-support-for-custom-macros/63868)) ([review](https://forums.swift.org/t/se-0394-package-manager-support-for-custom-macros/64170))
 
 ## Introduction