enclose YAML strings containing % with quotes

| Q             | A
| ------------- | ---
| Doc fix?      | yes
| New docs?     | no
| Applies to    | all
| Fixed tickets | #4029

Thanks @iamdto, did you spot some other occurences in the docs?
Given that this is the output of the command, I agree we should keep it highlited as text, not as yaml (and we should not add the quotes which are not part of the output).

Highlighting the YAML could be confusing if some user then expect the command output to be highlighted