fix incorrect usage of formatted string (more of them)

[mgoetzegb]

What

fix incorrect usage of formatted string, newly introduced by #90

output probably unchanged, but now go vet is happy that formatted strings are not misused

Why

Go vet is a mandatory check and with the updated go version is has more findings.

References

PR blocked by this: #89

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Conventional Commits Report

😢 No conventional commits found.

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Modver result

This report was generated by Modver,
a Go package and command that helps you obey semantic versioning rules in your Go module.

This PR does not require a change in your module’s version number.
(You might still consider bumping the patchlevel anyway.)