[stzn/the-swift-programming-language-jp] Pull request opened: #599 [Concurrency]Exampleの修正

[stzn/the-swift-programming-language-jp] Pull request opened: #600 [イニシャライザ]文字列定数→文字列リテラル

[stzn/the-swift-programming-language-jp] Pull request opened: #601 [属性]クラス、構造体、列挙型→クラスや構造体、列挙型