[pango: 1/3] Link to the CSS font-feature-settings docs for pango_attr_font_features_new

[Matthias Clasen <matthiasc src gnome org>]

commit d16803843748be6cba48b74e60fa58390e90ae6b
Author: Federico Mena Quintero <federico gnome org>
Date:   Tue Jun 8 13:41:41 2021 -0500

    Link to the CSS font-feature-settings docs for pango_attr_font_features_new
    
    Fixes https://gitlab.gnome.org/GNOME/pango/-/issues/565

 pango/pango-attributes.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)
---
diff --git a/pango/pango-attributes.c b/pango/pango-attributes.c
index ffd209d6..8b1d857b 100644
--- a/pango/pango-attributes.c
+++ b/pango/pango-attributes.c
@@ -1122,10 +1122,14 @@ pango_attr_gravity_hint_new (PangoGravityHint hint)
 
 /**
  * pango_attr_font_features_new:
- * @features: a string with OpenType font features, in CSS syntax
+ * @features: a string with OpenType font features, with the syntax of the [CSS
+ * font-feature-settings property](https://www.w3.org/TR/css-fonts-4/#font-rend-desc)
  *
  * Create a new font features tag attribute.
  *
+ * You can use this attribute to select OpenType font features like small-caps,
+ * alternative glyphs, ligatures, etc. for fonts that support them.
+ *
  * Return value: (transfer full): the newly allocated
  *   `PangoAttribute`, which should be freed with
  *   [method@Pango.Attribute.destroy]