Added back ticks to create index example (#179)

Author: julia-cb

modules/n1ql/pages/n1ql-language-reference/with-recursive.adoc

@@ -257,7 +257,7 @@ SELECT * FROM similar_items;
 ====
 [source,sqlpp]
 ----
-CREATE INDEX srcdestidx ON travel-sample.inventory.route( sourceairport, destinationairport );
+CREATE INDEX srcdestidx ON `travel-sample`.inventory.route( sourceairport, destinationairport );
 
 WITH RECURSIVE recroute AS (
     SELECT sourceairport, destinationairport, 0 as depth,
@@ -355,4 +355,4 @@ SELECT * FROM recroute LIMIT 2000;
 // ...
 ]
 ----
-====
+====