[gtk+] 3to4: Fix typo in previous commit

[Daniel Boles <dboles src gnome org>]

commit 19e2f347e185789ab39492bb63f492d15b1d0874
Author: Daniel Boles <dboles src gnome org>
Date:   Sat Jan 21 22:43:35 2017 +0000

    3to4: Fix typo in previous commit

 docs/reference/gtk/migrating-3to4.xml |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/docs/reference/gtk/migrating-3to4.xml b/docs/reference/gtk/migrating-3to4.xml
index ec06d47..7507821 100644
--- a/docs/reference/gtk/migrating-3to4.xml
+++ b/docs/reference/gtk/migrating-3to4.xml
@@ -169,7 +169,7 @@
       <para>
         GTK+ 4 has removed the #GtkContainer::border-width property.
         Use other means to influence the spacing of your containers,
-        such ss the CSS margin and padding properties on child widgets.
+        such as the CSS margin and padding properties on child widgets.
       </para>
     </section>