Suggest to add the file if config file is not found

[ColinFay]

Hey,

If there is no config file found, {shrtcts} throws an error:

> shrtcts::edit_shortcuts()
Error: Could not find .shrtcts.R or .shrtcts.yaml in /Users/colin/.config or /Users/colin

IMHO it would be more user-friendly to suggest to create this file :)

For ex:

> shrtcts::edit_shortcuts()
No short .shrtcts.R file found, wanna create it? 

1: Yes
2: No

[gadenbuie]

This is a good idea, thanks!