Fix link for TLS docs in apple-platforms.md (#1232)

docs/apple-platforms.md

@@ -24,4 +24,4 @@ See the [TLS docs][docs-tls] for more.
 
 [network-framework]: https://developer.apple.com/documentation/network
 [nio-ts]: https://github.com/apple/swift-nio-transport-services
-[docs-tls]: ./tls-start.md
+[docs-tls]: ./tls.md