Change outdated message so it applies to outdated and dev

Signed-off-by: David Martin <[email protected]>

overrides/main.html

@@ -1,7 +1,7 @@
 {% extends "base.html" %}
 
 {% block outdated %}
-  These docs are unstable, from our development branches (main).
+  These docs are not for the latest version.
   <a href="{{ '../' ~ base_url }}"> 
     <strong>Click here to go to latest, stable docs.</strong>
   </a>