Fix broken link in top of dev_guide/server.html
* Just fixing a typo so that the link at the top of dev_guide/server.html
correctly points to user_guide/server.html
@@ -4,7 +4,7 @@ Server Architecture
===================
This chapter is a "deep dive" into Bokeh server's internals. It assumes you're
-already familiar with the information on Bokeh server in the :ref`userguide`.
+already familiar with the information on Bokeh server in :ref:`userguide_server`.
You might want to read this if you are:
