Enabled relative paths for git remove. Updated add/remove labels. Added whitespace filter for user inputs.

[MichaelM1]

Now git remove can take relative paths as input. I also updated the labels for add/remove to not say "excluding the repository path" because we can also take in absolute paths. Also added a whitespace filter in case the user tries to add/remove something but leaves in whitespace in their input e.g. "file.py " instead of "file.py".

[air-wickvu]

Thanks for the fix, looks good on my end.