Link codemirror-vim from vim demo

Author: marijnh

demo/vim.html

@@ -31,12 +31,11 @@
 <article>
 <h2>Vim bindings demo</h2>
 
-<p><strong style="color: #c33; text-decoration: none">Note:</strong> The CodeMirror vim bindings do not have an
-active maintainer. That means that if you report bugs in it, they are
-likely to go unanswered. It also means that if you want to help, you
-are very welcome to look
-at <a href="https://github.com/codemirror/codemirror5/issues?q=is%3Aissue+is%3Aopen+label%3Avim">the
-open issues</a> and see which ones you can solve.</p>
+<p><strong style="color: #c33; text-decoration: none">Note:</strong>
+The CodeMirror vim bindings are maintained in
+the <a href="https://github.com/replit/codemirror-vim">codemirror-vim</a>
+repository, not this project. The file is still included in the
+distribution for backwards compatibility.</p>
 
 <form><textarea id="code" name="code">
 #include "syscalls.h"