Work around an unfortunate ICE

https://github.com/rust-lang/rust/issues/37274

src/lib.rs

@@ -762,7 +762,7 @@ impl Url {
     /// url.query_pairs_mut()
     ///     .clear()
     ///     .append_pair("foo", "bar & baz")
-    ///     .append_pair("saisons", "Été+hiver");
+    ///     .append_pair("saisons", "\u{00C9}t\u{00E9}+hiver");
     /// assert_eq!(url.query(), Some("foo=bar+%26+baz&saisons=%C3%89t%C3%A9%2Bhiver"));
     /// assert_eq!(url.as_str(),
     ///            "https://example.net/?foo=bar+%26+baz&saisons=%C3%89t%C3%A9%2Bhiver#nav");