Sets and asserts the file type argument to a standard format for further internal processing.
set_and_assert_arg_filetype(filetype)
A character vector with file types to convert to the internal standard format.
styler:::set_and_assert_arg_filetype("rMd")
#> [1] "\\.rmd"
try(styler:::set_and_assert_arg_filetype("xyz"))
#> Error in assert_filetype(without_dot) :
#> filetype must not contain other values than 'qmd', 'R', 'Rmarkdown', 'Rmd', 'Rnw', or 'Rprofile' (case is ignored).