[glib] docs: Correct inconsistency in GObject tutorial

[Philip Withnall <pwithnall src gnome org>]

commit f5dba7d43c597668382363c8677172298f28475c
Author: Ivar Trygve Jarlsby <ivartj ivartj org>
Date:   Sat Nov 25 21:20:59 2017 +0100

    docs: Correct inconsistency in GObject tutorial
    
    The example code defines an interface with three methods. The preceding text
    reads 'This interface defines two methods'. This appears to be because the
    example code was changed without updating the surrounding text.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=790830

 docs/reference/gobject/tut_howto.xml |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/docs/reference/gobject/tut_howto.xml b/docs/reference/gobject/tut_howto.xml
index 0696666..01391a9 100644
--- a/docs/reference/gobject/tut_howto.xml
+++ b/docs/reference/gobject/tut_howto.xml
@@ -860,7 +860,7 @@ b_method_to_call (B *obj, gint some_param)
 
   <para>
     The first step is to get the header right. This interface
-    defines two methods:
+    defines three methods:
 <informalexample><programlisting>
 /*
  * Copyright/Licensing information.