Function builtin_toml_serialize 

fn builtin_toml_serialize(
    args: &[RValue],
    _named: &[(String, RValue)],
) -> Result<RValue, RError>

Convert an R value to a TOML string.

Conversion rules:

• Named list -> TOML table
• Atomic vector of length 1 -> TOML scalar
• Atomic vector of length > 1 -> TOML array
• NULL -> omitted

@param x R value to convert (typically a named list) @return character scalar containing the TOML string