doc: replace deprecated output.html.curly-quotes

Author: weihanglo

Diff for: src/doc/book.toml

@@ -3,7 +3,7 @@ title = "The Cargo Book"
 author = "Alex Crichton, Steve Klabnik and Carol Nichols, with contributions from the Rust community"
 
 [output.html]
-curly-quotes = true # Enable smart-punctuation feature for more than quotes.
+smart-punctuation = true # Enable smart-punctuation feature for more than quotes.
 git-repository-url = "https://github.com/rust-lang/cargo/tree/master/src/doc/src"
 edit-url-template = "https://github.com/rust-lang/cargo/edit/master/src/doc/{path}"
 search.use-boolean-and = true