Rustdoc doesn't work on IE11. It's been broken for months, it isn't supported
by the [tiered browser support list], it's even more severely broken on other
Rust websites, and IE11 doesn't support the `<details>` tag that we want
to use.
In the interest of honesty, let's give an actual error message for anyone
on IE11.
[tiered browser support list]: https://github.com/rust-lang/rfcs/blob/master/text/1985-tiered-browser-support.md
</style>\
</head>\
<body class=\"rustdoc {css_class}\">\
- <!--[if lte IE 8]>\
+ <!--[if lte IE 11]>\
<div class=\"warning\">\
This old browser is unsupported and will most likely display funky \
things.\