Added string format to step_walker

[guitared]

Short Description:

Added string format for location in step_walker.py

[mention-bot]

@guitared, thanks for your PR! By analyzing the annotation information on this pull request, we identified @douglascamata, @TheSavior and @asnelzin to be potential reviewers

[elicwhite]

I don't think this is the right fix. This should only be printed out in debug mode, but it is getting printed even when not in debug mode. @douglascamata how do we fix this?

[ryanb93]

@TheSavior I think this is because of the coloured_logging_handler using sys.stdout.write and the 'level' parameter being passed through isn't being used at all.

[douglascamata]

The coloured logging handler should be fixed to use the logging module correctly as the normal logging handler uses.

[douglascamata]

#3637 will fix this properly by fixing the coloured log handler implementation.