[gtk] docs: fix a typo

[Matthias Clasen <matthiasc src gnome org>]

commit 74455ae75c9038f395107f32b5f31abd01b19438
Author: Matthias Clasen <mclasen redhat com>
Date:   Tue Jun 19 16:46:53 2018 -0400

    docs: fix a typo
    
    Invalid syntax in gdk4-sections.txt was causing docs builds to fail.

 docs/reference/gdk/gdk4-sections.txt | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/docs/reference/gdk/gdk4-sections.txt b/docs/reference/gdk/gdk4-sections.txt
index 21d1ed2934..f36e5b3a5e 100644
--- a/docs/reference/gdk/gdk4-sections.txt
+++ b/docs/reference/gdk/gdk4-sections.txt
@@ -694,7 +694,7 @@ gdk_event_get_type
 
 <SECTION>
 <FILE>gdkpaintable</FILE>
-<TITLE>GdkPaintable/TITLE>
+<TITLE>GdkPaintable</TITLE>
 GdkPaintable
 GdkPaintableFlags
 gdk_paintable_get_current_image