gh-924: implemented `ToPercentRounded`

[MKadaner]

Summary

Implemented proper rounding when representing ratios as percents.

References

• gh-924

Checklist

• [X] I have followed the contributing guidelines.
• [ ] I have discussed this with project maintainers:
  If not checked, I accept that this work might be rejected in favor of a different great big ineffable plan.
  

Details

@alabuzhev, please let me know if you want it turned into a proper PR.

[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

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