[gnome-builder] doc: fix cross-document ref

[Christian Hergert <chergert src gnome org>]

commit 2cebd568d612527baafeae11ad0bb16833465dce
Author: Christian Hergert <chergert redhat com>
Date:   Wed Apr 26 12:34:33 2017 -0700

    doc: fix cross-document ref

 doc/contributing/code.rst |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/doc/contributing/code.rst b/doc/contributing/code.rst
index 7288a5c..2d93273 100644
--- a/doc/contributing/code.rst
+++ b/doc/contributing/code.rst
@@ -28,7 +28,7 @@ For example, the git_ plugin is the glue between the version control abstraction
 
 There are many `existing plugins`_ already.
 You might want to contribute to an existing one that does not yet serve your needs well.
-Or maybe you want to `create a new plugin<creating_plugins>` that integrates a feature missing from Builder.
+Or maybe you want to :ref:`create a new plugin<creating_plugins>` that integrates a feature missing from 
Builder.
 
 .. _libide: https://git.gnome.org//browse/gnome-builder/tree/libide/
 .. _git: https://git.gnome.org//browse/gnome-builder/tree/plugins/git/