Add Unit Test for ctil::ends_with in test.cpp

[rjwignar]

ctil::ends_with() is a helper method that checks if a string, value, ends with a suffix, ending. This method is used to check if file paths passed to ctil contains specific file extensions. A unit test has to be added to test.cpp that tests ctil::ends_with().

To do this:

• Clone the repository's master branch.
• Open ctil.sln in Visual Studio (2019 or 2022).
• Add your test to test.cpp.
• Unit tests are written in Google Tests.
  • A primer on Google Test is available here.
  • You can refer to the primer or refer to other tests written in test.cpp for examples.

[kliu57]

I can work on this :)