Fix a tiny typo in _Step docstring

[sadra-barikbin]

Hi there!

To fix a teeny-tiny typo in _Step docstring.

[codspeed-hq]

CodSpeed Performance Report

Merging #1051 will not alter performance

_{Comparing sadra-barikbin:Fix-tiny-typo-in-step-docstring (08917c2) with develop (7c8976b)}

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Summary

✅ 1 untouched benchmarks

[plaguss]

Thanks for the catch!