Document all support API timestamp formats. (#5439)
Document all support API timestamp formats. (#5439)

Co-authored-by: Karen Miller <ef8557dee2454782e1ca8165e06aa3aaae92367b@users.noreply.github.com>
grafana/loki,grafana/loki,grafana/loki,grafana/loki,grafana/loki,grafana/loki