Add announcement header for deprecation

cketti · cketti · commit 109f5d45b13f · 2024-08-26T12:26:20.000+02:00
diff --git a/overrides/main.html b/overrides/main.html
@@ -0,0 +1,5 @@
+{% extends "base.html" %}
+
+{% block announce %}
+  This user manual is deprecated. Please ask for help in the <a href="https://forum.k9mail.app/">user forum</a> instead.
+{% endblock %}
