Add --lint-fatal option (#10815)
Add --lint-fatal option (#10815)

This keeps the previous behaviour of printing details about duplicate
rules but doesn't exit with a fatal exit code unless turned on.

Signed-off-by: David Leadbeater <4403351474a7bf43275d0cd941e1f9895fa27820@dgl.cx>
prometheus/prometheus,prometheus/prometheus,prometheus/prometheus,prometheus/prometheus,prometheus/prometheus