[gtk+] docs: Fix a duplicate id

[Matthias Clasen <matthiasc src gnome org>]

commit 69a38a9771350a6fc16d49704db681a317fca318
Author: Matthias Clasen <mclasen redhat com>
Date:   Fri Jan 29 08:08:08 2016 -0500

    docs: Fix a duplicate id
    
    This was causing the css properties chapter to appear twice
    in the docs, and the overview not at all.

 docs/reference/gtk/css-properties.xml |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/docs/reference/gtk/css-properties.xml b/docs/reference/gtk/css-properties.xml
index 4c804a4..09fcc0b 100644
--- a/docs/reference/gtk/css-properties.xml
+++ b/docs/reference/gtk/css-properties.xml
@@ -2,7 +2,7 @@
 <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.3//EN"
                "http://www.oasis-open.org/docbook/xml/4.3/docbookx.dtd"; [
 ]>
-<refentry id="chap-css-overview">
+<refentry id="chap-css-properties">
 <refmeta>
 <refentrytitle>GTK+ CSS</refentrytitle>
 <manvolnum>3</manvolnum>