[r mode] Remove license link

All of the distribution is under a single license.

Author: marijnh

mode/r/index.html

@@ -80,7 +80,6 @@ <h2>R mode</h2>
     <p><strong>MIME types defined:</strong> <code>text/x-rsrc</code>.</p>
 
     <p>Development of the CodeMirror R mode was kindly sponsored
-    by <a href="http://ubalo.com/">Ubalo</a>, who hold
-    the <a href="LICENSE">license</a>.</p>
+    by <a href="http://ubalo.com/">Ubalo</a>.</p>
 
   </article>