Add build date to docs

Makes it easier to spot when the docs aren't rebuilding correctly.

diff --git a/docs/source/index.rst b/docs/source/index.rst
index dc8bacc719b8c3815366ba15f0c1c64645f85e74..3b13b1bca3e3d741d1e6d559e9891cc2dcf0db36 100644 (file)
--- a/docs/source/index.rst
+++ b/docs/source/index.rst
@@ -57,3 +57,4 @@ Indices and tables
 
 .. * :ref:`modindex`
 
+This guide was built on |today|.