docs(dogstatsd): regenerate dogstatsd.md (#1668)

## Summary

Reran `/confkey audit-all`. Identified one new config option we don't support yet [`aggregator_tag_filter_cache_capacity`](#1667).

Recommend just reviewing the dogstatsd.md file with whitespace ignored.

Co-authored-by: jesse.szwedko <jesse.szwedko@datadoghq.com>

Author: jszwedko