[Describe your changes and what you've already done to test it.]

• Fix typo in the header documentation
• Solve linker error caused by typo in the bottom of the header file (including wrong file)

Check all that apply (change to [x])

• All changes meet libigl style-guidelines.
• Adds new .cpp file.
• Adds corresponding unit test.
• Adds corresponding python binding.
• This is a minor change.