Considering a tidy_post_fun argument to tidy_plus_plus()

[larmarange]

The idea is to allow advanced users to pass a custom function to be applied at the end of tidy_plus_plus() for customizing the final results.

It could be useful when just basic support is available for a model.

[larmarange]

Following larmarange/ggstats#42 and ddsjoberg/gtsummary#1545, I was thinking that it could be relevant to have an easy to pass custom changes to the produced tibble through tidy_plus_plus()

The changes need to beap plied at the end of tidy_plus_plus(). The post_fun argument allows to pass a custom function at the end of the process.

@ddsjoberg What do you think?

[larmarange]

Should the name be rather tidy_podt_fun? Or smth more explicit?