rustc book: make more pleasant to search

Author: tshepang

src/doc/rustc/book.toml

@@ -7,5 +7,8 @@ title = "The rustc book"
 git-repository-url = "https://github.com/rust-lang/rust/tree/master/src/doc/rustc"
 edit-url-template = "https://github.com/rust-lang/rust/edit/master/src/doc/rustc/{path}"
 
+[output.html.search]
+use-boolean-and = true
+
 [output.html.playground]
 runnable = false