Add acceptance link to SE-0422 (#2319)

Author: DougGregor

proposals/0422-caller-side-default-argument-macro-expression.md

@@ -5,7 +5,7 @@
 * Review Manager: [Doug Gregor](https://github.com/DougGregor)
 * Status: **Accepted**
 * Implementation: [PR #70602](https://github.com/apple/swift/pull/70602) with experimental feature flag `ExpressionMacroDefaultArguments`
-* Review: ([Review](https://forums.swift.org/t/se-0422-expression-macro-as-caller-side-default-argument/69730))([Pitch](https://forums.swift.org/t/pitch-expression-macro-as-caller-side-default-argument/69019))
+* Review: ([Review](https://forums.swift.org/t/se-0422-expression-macro-as-caller-side-default-argument/69730))([Pitch](https://forums.swift.org/t/pitch-expression-macro-as-caller-side-default-argument/69019))([Acceptance](https://forums.swift.org/t/accepted-se-0422-expression-macro-as-caller-side-default-argument/70050))
 
 ## Introduction