No examples of create/build index in SDK documentation

Was going through https://docs.couchbase.com/go-sdk/current/howtos/n1ql-queries-with-sdk.html and I do not see any examples of how to create index in the documentation.

One has to go through https://github.com/couchbase/docs-sdk-go/blob/b47bef545e9e0b2212b0d4c678b58a0aada4da6d/modules/howtos/examples/query-index-manager.go#L57 to understand how to create indexes.

I believe we should update our documentation to add more examples on how to create different types of indexes.