[Docs] consul_sd_config: Add default value for `allow_stale` (#7075)
[Docs] consul_sd_config: Add default value for `allow_stale` (#7075)

Ref: https://github.com/prometheus/prometheus/blob/master/discovery/consul/consul.go#L97
Signed-off-by: Frederic Hemberger <1d6e1cf70ec6f9ab28d3ea4b27a49a77654d370e@frederic-hemberger.de>
keegancsmith/prometheus,keegancsmith/prometheus,keegancsmith/prometheus,GoogleCloudPlatform/prometheus,Gouthamve/prometheus,GoogleCloudPlatform/prometheus,kangwoo/prometheus,alileza/prometheus,prometheus/prometheus,kangwoo/prometheus,Gouthamve/prometheus,prometheus/prometheus,kangwoo/prometheus,GoogleCloudPlatform/prometheus,prometheus/prometheus,GoogleCloudPlatform/prometheus,prometheus/prometheus,kangwoo/prometheus,prometheus/prometheus,alileza/prometheus,alileza/prometheus,alileza/prometheus,Gouthamve/prometheus,keegancsmith/prometheus,GoogleCloudPlatform/prometheus,alileza/prometheus,Gouthamve/prometheus,keegancsmith/prometheus