Fix mispelling in define step command error message

[clrudolphi]

Fix a misspelled word in an error message within the DefineStepsCommand.

Types of changes

• [X] Bug fix (non-breaking change which fixes an issue).
• [ ] New feature (non-breaking change which adds functionality).
• [ ] Breaking change (fix or feature that would cause existing functionality to not work as expected).
• [ ] Performance improvement
• [ ] Refactoring (so no functional change)
• [ ] Other (docs, build config, etc)

Checklist:

• [ ] I've added tests for my code. (most of the time mandatory)
• [X] I have added an entry to the changelog. (mandatory)
• [ ] My change requires a change to the documentation.
• [ ] I have updated the documentation accordingly.