[gtk-doc] mkhtml2: chapter titles are <h2>

[Stefan Sauer <stefkost src gnome org>]

commit 33ccd2ae2c95f5c7dfe54a345a9f12c28173cd2f
Author: Stefan Sauer <ensonic users sf net>
Date:   Sun Mar 25 19:45:53 2018 +0200

    mkhtml2: chapter titles are <h2>

 gtkdoc/mkhtml2.py |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/gtkdoc/mkhtml2.py b/gtkdoc/mkhtml2.py
index 2077de5..1b5d29f 100644
--- a/gtkdoc/mkhtml2.py
+++ b/gtkdoc/mkhtml2.py
@@ -835,7 +835,7 @@ def convert_chapter(ctx):
     ]
     title = node.xml.find('title')
     if title is not None:
-        result.append('<div class="titlepage"><h1 class="title"><a name="%s"></a>%s</h1></div>' % (
+        result.append('<div class="titlepage"><h2 class="title"><a name="%s"></a>%s</h2></div>' % (
             get_id(node), title.text))
         node.xml.remove(title)
     convert_inner(ctx, node.xml, result)