fix linter issue in installer/operators-check.md
The linter job for was overridden, so invalid markdown landed. This
fixes the markup to make the job work for other PRs.
@@ -81,10 +81,8 @@ None
The important detail is how we define _stable_. The definition proposed here is:
-```
-If a cluster operator does not maintain Progressing=False for at least 30 seconds,
-during a five minute period it is unstable.
-```
+> If a cluster operator does not maintain Progressing=False for at least 30 seconds,
+> during a five minute period it is unstable.
### Risks and Mitigations
