Fixing a bad URL that sends the user to docs if they have an open site (

nightscout#7005)

Fixing a bad URL that sends the user to docs if they have an open site 
http://nightscout.github.io/nightscout/security/#how-to-turn-off-unauthorized-access

Co-authored-by: Sulka Haro <sulka@sulka.net>

lib/server/bootevent.js

@@ -121,7 +121,7 @@ function boot (env, language) {
     if (env.settings.authDefaultRoles == 'readable') {
       const message = {
         title: "Nightscout readable by world"
-        ,message: "Your Nightscout installation is readable by anyone who knows the web page URL. Please consider closing access to the site by following the instructions in the <a href=\"http://nightscout.github.io/nightscout/admin_tools/#turn-off-unauthorized-access\" target=\"_new\">Nightscout documentation</a>."
+        ,message: "Your Nightscout installation is readable by anyone who knows the web page URL. Please consider closing access to the site by following the instructions in the <a href=\"http://nightscout.github.io/nightscout/security/#how-to-turn-off-unauthorized-access\" target=\"_new\">Nightscout documentation</a>."
         ,persistent: true
       };
       ctx.adminnotifies.addNotify(message);