Fix invalid HTML escape

src/test/rustdoc/double-quote-escape.rs

@@ -0,0 +1,23 @@
+// Copyright 2017 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+#![crate_name = "foo"]
+
+// ignore-tidy-linelength
+
+pub trait Foo<T> {
+    fn foo() {}
+}
+
+pub struct Bar;
+
+// @has foo/struct.Bar.html
+// @has - '//*[@class="sidebar-links"]/a[@href="#impl-Foo%3Cunsafe%20extern%20%22C%22%20fn()%3E"]' 'Foo<unsafe extern "C" fn()>'
+impl Foo<unsafe extern "C" fn()> for Bar {}