Add alchemist.vim to editor list (elixir-lang#865)

Author: slashmili

_includes/important-links.html

@@ -27,6 +27,7 @@ <h3 class="widget-title">Code editor support</h3>
     <li><a class="spec" href="https://github.com/elixir-lang/elixir-tmbundle">TextMate / Sublime Text Bundle</a></li>
     <li><a class="spec" href="https://github.com/vishnevskiy/ElixirSublime">Sublime Plugin</a></li>
     <li><a class="spec" href="https://github.com/elixir-lang/vim-elixir">Vim Elixir</a></li>
+    <li><a class="spec" href="https://github.com/slashmili/alchemist.vim">Alchemist.vim (Vim Elixir Tooling)</a></li>
     <li><a class="spec" href="https://github.com/SteffenBauer/elixir-gtksourceview">GtkSourceView (gedit)</a></li>
     <li><a class="spec" href="https://github.com/lucasmazza/language-elixir">Atom Package</a></li>
     <li><a class="spec" href="https://github.com/KronicDeth/intellij-elixir">IntelliJ Elixir</a></li>