The reason is avoid collision with AtkObject.html on case-insensitive
filesystems.
One could argue that having a small html that just list AtkObject,
but this is done automatically by gtk-doc.
One could argue again, saying that probably the current chapter-split
main page (at atk-docs.sgml) is not the correct one, but I think
that for now a small id rename is better that a full main page
overhaul.
https://bugzilla.gnome.org/show_bug.cgi?id=772236
</chapter>
- <chapter id="atkobject">
+ <chapter id="base-object">
<title>Base accessibility object</title>
&atk-AtkObject;
</chapter>