Function interp_help 

fn interp_help(
    args: &[RValue],
    named: &[(String, RValue)],
    context: &BuiltinContext<'_>,
) -> Result<RValue, RError>

Display help for a function.

@param topic name of the function to look up @param package restrict search to this package (used by binary ?, e.g. methods?show)