Fix reversal potential inference and docstring for detect_ramp_bounds

[joeyshuttleworth]

Description

Fix reversal potential inference due to a mismatch in what is returned from detect_ramp_bounds. Update/correct detect_ramp_bounds docstring and variable/parameter names. Closes #99.

Includes new test for infer_reversal_potential().

Types of changes

• 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 change)

Testing

• Testing is done automatically and codecov shows test coverage
• This cannot be tested automatically

Documentation checklist

• I have updated all documentation in the code where necessary.
• I have checked spelling in all (new) comments and documentation.
• I have added a note to RELEASE.md if relevant (new feature, breaking change, or notable bug fix).

[joeyshuttleworth]

Parameter name was a bit confusing here

[joeyshuttleworth]

These lines were causing infer reversal potential to fail for every single trace