message: Rust dropdown now directly links to rust-lang.org
  The "Rust" topbar dropdown is now consistent in functionality with the
  other dropdowns by linking directly to an item.
diff: {# The Rust dropdown menu #}
  <li class="pure-menu-item pure-menu-has-children pure-menu-allow-hover">
  - <a href="#" class="pure-menu-link">Rust</a>
  + <a href="https://www.rust-lang.org/" target="_blank" class="pure-menu-link">Rust</a>
  <ul class="pure-menu-children">
  - {{ macros::menu_link(
  - href="https://www.rust-lang.org/",
  - text="The Rust Programming Language",
  - target="_blank"
  - ) }}
  -
  {{ macros::menu_link(
  href="https://doc.rust-lang.org/book/",
  text="The Book",
  