This is a helper function for style_dir.
prettify_any(transformers, filetype, recursive, exclude_files)A set of transformer functions. This argument is most
conveniently constructed via the style argument and .... See
'Examples'.
Vector of file extensions indicating which filetypes should
be styled. Case is ignored, and the . is optional, e.g. c(".R", ".Rmd")
or c("r", "rmd").
A logical value indicating whether or not files in subdirectories should be styled as well.
Character vector with paths to files that should be excluded from styling.