Better document that each shortcut needs to a function (or wrapped in one)

[gadenbuie]

Fortunately, the fix is pretty easy. Each shortcut needs to be encapsulated in a function. The doesn't need to be a named, but it helps and I recommend it:

Hey, @gadenbuie 👋 Maybe you can add this into the README file or in the Get Started section? I have also encountered this issue. Unfortunately, it's not really straightforward from the package documentation that it's better to wrap all shortcuts in functions :(

Originally posted by @atsyplenkov in https://github.com/gadenbuie/shrtcts/issues/24#issuecomment-2016977267

[gadenbuie]

The quick start guide includes this instruction, but it's a little too opaque and the following example shows a packaged function rather than a user-created function.

https://github.com/gadenbuie/shrtcts/blob/41051cf25ee8bfd66da45315013ade9d894435bd/man/fragments/shrtcts-quick-start.Rmd#L13-L15