[ci] Fix comment in iwyu.yml [skip ci]

[gruenich]

Comments need to be properly indented.

[gruenich]

Marking as draft, as I was not able to trigger the iwyu action in my personal fork or this repository. I could not verify if this pull request really fixes the issue.

[sonarqubecloud[bot]]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[firewave]

Marking as draft, as I was not able to trigger the iwyu action in my personal fork or this repository. I could not verify if this pull request really fixes the issue.

As the current version works in trunk I think this is just a formatting issue which has no impact on the execution of this.