fix(yaml): promql injections block

tests/query/injections/yaml/promql-on-prometheus-rules.yaml

@@ -10,3 +10,10 @@ groups:
     annotations:
       title: Node {{ $labels.instance }} is down
       description: Failed to scrape {{ $labels.job }} on {{ $labels.instance }} for more than 3 minutes. Node seems down.
+  - alert: Node down
+    expr: |
+      up{job="node_exporter"} == 0
+    # ^ promql
+    for: 3m
+    labels:
+      severity: warning