Recursive example does not include back ticks on index creation

PR link: https://github.com/couchbaselabs/docs-devex/pull/179

On this page https://docs.couchbase.com/server/current/n1ql/n1ql-language-reference/with-recursive.html the sample create index code reads like this:

CREATE INDEX srcdestidx ON travel-sample.inventory.route( sourceairport, destinationairport );

This statement fails without the back-ticks around travel-sample.  Should read:

CREATE INDEX srcdestidx ON `travel-sample`.inventory.route( sourceairport, destinationairport );