update buildbot doc to link to the new Appveyor builders

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@302116 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/docs/index.rst b/docs/index.rst
index 58043f5..e69963b 100644
--- a/docs/index.rst
+++ b/docs/index.rst
@@ -145,7 +145,7 @@
 
 * `LLVM Buildbot Builders <http://lab.llvm.org:8011/console>`_
 * `Apple Jenkins Builders <http://lab.llvm.org:8080/green/view/Libcxx/>`_
-* `EricWF's Nightly Builders <http://ds2.efcs.ca:8080/console>`_
+* `Windows Appveyor Builders <https://ci.appveyor.com/project/EricWF/libcxx>`_
 * `Code Coverage Results <http://efcs.ca/libcxx-coverage>`_
 
 Getting Involved