Create KeyboardListener documentation

[Empiree]

This task is part of the larger Create API documentation task.

Help from newcomers is welcome!

While solving this task, you can familiarize yourself with the library functionality and help other users to work with it.

To create documentation, please pay attention to the README file. The documentation should be designed in this style, and fully disclose all the features of the KeyboardListener class. If you have any ideas for new features of this class while writing documentation, please create a new issue and describe your idea.

Place the documentation in the Documentation.md file!

If you have any questions, feel free to post them here! Our project is beginner friendly!