Update navigation

- Simplify nav header
 - Use index for main Dev Doc page (instead of separate page)

_translations/en.yml

@@ -84,10 +84,11 @@ en:
       Most security is handled by the protocol, eliminating the need for
       PCI compliance. Fraud prevention can be simplified down to
       monitoring a single variable: the <a
-      href="#you-need-to-know##instant">confirmation score</a>. Beyond
+      href="#vocabulary##confirmation">confirmation count</a>. Beyond
       that, keeping
-      your Dash secure is mainly a matter of <a
-      href="#secure-your-wallet#">securing your wallet</a> and using
+      your Dash secure is mainly a matter of
+      securing your wallet
+      and using
       HTTPS or other secure protocols to send payment requests to customers.
 
     micro: "New payment possibilities"
@@ -871,6 +872,7 @@ en:
     menu-bitcoin-for-individuals: Individuals
     menu-community: Community
     menu-development: Development
+    menu-documentation: Documentation
     menu-events: Events
     menu-exchanges: Exchanges
     menu-faq: FAQ