[pango] Document font_features support in markup

[Matthias Clasen <matthiasc src gnome org>]

commit 7aa0aa0aabaf08e2500b7e267010a42d36918ce9
Author: Matthias Clasen <mclasen redhat com>
Date:   Thu Jul 30 13:31:06 2015 -0400

    Document font_features support in markup

 docs/pango_markup.sgml |    8 ++++++++
 1 files changed, 8 insertions(+), 0 deletions(-)
---
diff --git a/docs/pango_markup.sgml b/docs/pango_markup.sgml
index 227b413..913ece6 100644
--- a/docs/pango_markup.sgml
+++ b/docs/pango_markup.sgml
@@ -124,6 +124,14 @@ One of 'ultracondensed', 'extracondensed', 'condensed',
 </varlistentry>
 
 <varlistentry>
+<term>font_features<footnote><para>Since 1.38</para></footnote></term>
+<listitem><para>
+A comma separated list of OpenType font feature settings, in the same
+syntax as accepted by CSS. E.g: <literal>font_features='dlig=1, -kern, afrc on'</literal>
+</para></listitem>
+</varlistentry>
+
+<varlistentry>
 <term>foreground</term>
 <term>fgcolor<footnoteref linkend='since_1_21'/></term>
 <term>color</term>