Mark SE-0269 as implemented (#1114)

* Mark SE-0269 as implemented

* Update Swift implemented version

Author: Jumhyn

proposals/0269-implicit-self-explicit-capture.md

@@ -3,7 +3,7 @@
 * Proposal: [SE-0269](0269-implicit-self-explicit-capture.md)
 * Author: [Frederick Kellison-Linn](https://github.com/jumhyn)
 * Review Manager: [Ted Kremenek](https://github.com/tkremenek)
-* Status: **Accepted**
+* Status: **Implemented (Swift 5.3)**
 * Implementation: [apple/swift#23934](https://github.com/apple/swift/pull/23934)
 * Bug: [SR-10218](https://bugs.swift.org/browse/SR-10218)
 * Forum threads: [Discussion](https://forums.swift.org/t/review-capture-semantics-of-self/22017), [Pitch](https://forums.swift.org/t/allow-implicit-self-in-escaping-closures-when-self-is-explicitly-captured/22590), [Review thread](https://forums.swift.org/t/se-0269-increase-availability-of-implicit-self-in-escaping-closures-when-reference-cycles-are-unlikely-to-occur/30376)