releasing: Correct documentation for script name

Signed-off-by: Bryce Harrington <bryce@osg.samsung.com>
diff --git a/releasing.txt b/releasing.txt
index 3b0dbff..131ff31 100644
--- a/releasing.txt
+++ b/releasing.txt
@@ -69,7 +69,7 @@
   7.  Update releases.html in wayland-web with links to tarballs and
       the release email URL.
 
-      The register_release script in wayland-web will generate an HTML
+      The wl_register_release script in wayland-web will generate an HTML
       snippet that can be pasted into releases.html (or e.g. in emacs
       insert it via "C-u M-! scripts/register_release x.y.z") and
       customized.