Enable selective word emphasis within a sentence

[k5cents]

It could be useful to allow the emphasis functions to target a specific word of a sentence.

From a string like this we would bold only the 5th word.

Could possibly be done with stringr::word().

Maybe a separate function, rather than another argument to each function?

[k5cents]

Not very satisfied with this solution, but it works for now. Using stringr::word() would allow for more flexible word selection for emphasis.