Fix clang-tidy quirk

[knelli2]

Proposed changes

My bad for missing this. It's causing clang-tidy to fail on all PRs that have been rebased.

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Code review checklist

• The code is documented and the documentation renders correctly. Run
  make doc to generate the documentation locally into BUILD_DIR/docs/html.
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• The code follows the stylistic and code quality guidelines listed in the
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