[gtk+] docs: replace another envar that sneaked in

[William Jon McCann <mccann src gnome org>]

commit 9ff678c37fc7ee16cd803939c43dbea49e0c3856
Author: William Jon McCann <william jon mccann gmail com>
Date:   Tue Feb 4 17:25:37 2014 -0500

    docs: replace another envar that sneaked in

 gdk/gdkscreen.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/gdk/gdkscreen.c b/gdk/gdkscreen.c
index b25a5ca..9423b8d 100644
--- a/gdk/gdkscreen.c
+++ b/gdk/gdkscreen.c
@@ -920,7 +920,7 @@ gdk_screen_get_rgba_visual (GdkScreen *screen)
  *
  * This will be the visual returned by gdk_screen_get_rgba_visual()
  * unless that is not available, or unless the environment
- * variable <envar>GDK_RGBA</envar> is set to 0.
+ * variable `GDK_RGBA` is set to `0`.
  *
  * Return value: (transfer none): the preferred visual to use
  *     for windows