[gtk] docs: fix typo

[Claudio Saavedra <csaavedra src gnome org>]

commit 0af16a77fc79cf01818cedaa427432987c052983
Author: Claudio Saavedra <csaavedra igalia com>
Date:   Tue Apr 21 14:49:13 2020 +0300

    docs: fix typo

 docs/reference/gtk/migrating-3to4.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/docs/reference/gtk/migrating-3to4.xml b/docs/reference/gtk/migrating-3to4.xml
index f1f8455b19..67290812e1 100644
--- a/docs/reference/gtk/migrating-3to4.xml
+++ b/docs/reference/gtk/migrating-3to4.xml
@@ -399,7 +399,7 @@
         Any APIs that deal with global (or root) coordinates have been
         removed in GTK4, since not all backends support them. You should
         replace your use of such APIs with surface-relative equivalents.
-        Examples of this are gdk_surfae_get_origin(), gdk_surface_move()
+        Examples of this are gdk_surface_get_origin(), gdk_surface_move()
         or gdk_event_get_root_coords().
       </para>
     </section>