yml_verbatim: Write YAML field or content verbatim
Description
yml_verbatim() is a helper function to write YAML precisely as given to the
yml_*() function rather than the defaults in ymlthis and yaml. ymlthis uses
the yaml package to check for valid syntax; yaml and ymlthis together make
decisions about how to write syntax, which can often be done in numerous
valid ways. See yaml::as.yaml() for more details.