[stzn/the-swift-programming-language-jp] New comment on pull request #389: 各章にサマリを追加

[stzn/the-swift-programming-language-jp] Pull request closed: #389 各章にサマリを追加

[stzn/the-swift-programming-language-jp] Issue closed: #365 各章に概要の追加

[stzn/the-swift-programming-language-jp] Issue opened: #390 Non Sendableの明示方法(@available(*, unavailable))追加