[gnome-builder] doc: shorten plugins title

[Christian Hergert <chergert src gnome org>]

commit 263c7db8a438bf789dae04e6978c64f8376533ad
Author: Christian Hergert <chergert redhat com>
Date:   Wed Mar 8 18:59:16 2017 -0800

    doc: shorten plugins title

 doc/plugins/index.rst |    6 +++---
 1 files changed, 3 insertions(+), 3 deletions(-)
---
diff --git a/doc/plugins/index.rst b/doc/plugins/index.rst
index 3716dae..2afb070 100644
--- a/doc/plugins/index.rst
+++ b/doc/plugins/index.rst
@@ -1,8 +1,8 @@
 .. _creating_plugins:
 
-################
-Creating Plugins
-################
+#######
+Plugins
+#######
 
 The following provides examples of various ways you can extend Builder.
 All examples are provided in the Python 3 language for succinctness.