fix missed f-strings

[Borda]

What does this PR do?

Fixes #2657

Before submitting

• Was this discussed/agreed via a Github issue? (no need for typos and docs improvements)
• Did you read the contributor guideline, Pull Request section?
• Did you make sure to update the docs?
• Did you write any new necessary tests?

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📚 Documentation preview 📚: https://torchmetrics--2667.org.readthedocs.build/en/2667/

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 3 lines in your changes missing coverage. Please review.

Project coverage is 69%. Comparing base (e702807) to head (9c50291).

Additional details and impacted files

@@          Coverage Diff           @@
##           master   #2667   +/-   ##
======================================
- Coverage      69%     69%   -0%     
======================================
  Files         316     316           
  Lines       17881   17881           
======================================
- Hits        12331   12322    -9     
- Misses       5550    5559    +9