Documentation should be updated to reflect Mac substitution of CMD for CTRL where Windows shortcuts are mentioned

[ssawczyn]

While the documentation does a great job of mentioning specific VS Code keystrokes for Windows users, Mac shortcuts are not always provided. In general the keystrokes are the same with CMD substituting for CTRL. This issue suggests that a brief section be added to the documentation, chapter 0, indicating that Mac users should substitute CMD for CTRL whenever standard Windows keyboard shortcuts are mentioned. I think this would be preferable to listing Mac keyboard shortcuts throughout the documentation since substituting CMD for CTRL is the main difference.