Concatenate a list into a nice, comma-separated string. Useful when called from another shortcut as a method.

Example:

1. Prompt the user to pick from a list (or provide an entire list). Let's say the list is [dog,cat,llama,pig]
2. Call this shortcut
3. The shortcut will return a string: dog, cat, llama, and pig

The final word and can be customized, as can the Oxford (final) comma. It's on by default because I'm not a psychopath.