WIP: Elasticsearch only finds first occurrence in a file

Open Valery Sizov requested to merge es_code_highlight into master

What does this MR do?

It shows few occurrences for the same file.

Are there points in the code the reviewer needs to double check?

Why was this MR needed?

Screenshots (if relevant)

Does this MR meet the acceptance criteria?

What are the relevant issue numbers?

closes https://gitlab.com/gitlab-org/gitlab-ee/issues/668

Edited by Valery Sizov