Fix typo in SD docs
Fix typo in SD docs

Signed-off-by: Nick Triller <5c475cbb38a3cd4b4eb7c21abecffedd599eb553@gmail.com>

prometheus/prometheus,keegancsmith/prometheus,alileza/prometheus,keegancsmith/prometheus,GoogleCloudPlatform/prometheus,prometheus/prometheus,alileza/prometheus,keegancsmith/prometheus,prometheus/prometheus,alileza/prometheus,keegancsmith/prometheus,keegancsmith/prometheus,GoogleCloudPlatform/prometheus,GoogleCloudPlatform/prometheus,prometheus/prometheus,alileza/prometheus,alileza/prometheus,GoogleCloudPlatform/prometheus,prometheus/prometheus,GoogleCloudPlatform/prometheus