Wrapper around getOption("readr.show_col_types")
that implements some fall
back logic if the option is unset. This returns:
TRUE
if the option is set toTRUE
FALSE
if the option is set toFALSE
FALSE
if the option is unset and we appear to be running testsNULL
otherwise, in which case the caller determines whether to show column types based on context, e.g. whethershow_col_types
or actualcol_types
were explicitly specified