abci: reorder sidebar (#282)

spec/abci/abci.md

@@ -1,3 +1,8 @@
+---
+order: 1
+title: Method and Types
+---
+
 # Methods and Types
 
 ## Overview

spec/abci/apps.md

@@ -1,3 +1,8 @@
+---
+order: 2
+title: Applications
+---
+
 # Applications
 
 Please ensure you've first read the spec for [ABCI Methods and Types](abci.md)

spec/abci/client-server.md

@@ -1,3 +1,8 @@
+---
+order: 3
+title: Client and Server
+---
+
 # Client and Server
 
 This section is for those looking to implement their own ABCI Server, perhaps in