Add extendr_fn_options (better name?) to rust_function(), which accepts a named list of scalar values, each translating to an option passed to #[extendr] attribute.
Maintain a list of known options, such as use_try_from, r_name, mod_name.
Raise warnings on unknown options.
Verify types of known options
Abort if type mismatch, if an option has NULL value, or if the name is malformed.
extendr_fn_options(better name?) torust_function(), which accepts a namedlistof scalar values, each translating to an option passed to#[extendr]attribute.use_try_from,r_name,mod_name.NULLvalue, or if the name is malformed.Closes #131