[BUG] When we return to the API, do not vectorise the result

[bee-san]

/// // The result is an Option<DecoderResult> so we need to unwrap it
/// // The DecoderResult contains the text and the path
/// // The path is a vector of CrackResults which contains the decoder used and the keys used
/// // The text is a vector of strings because some decoders return more than 1 text (Caesar)
/// // Becuase the program has returned True, the first result is the plaintext (and it will only have 1 result).
/// // This is some tech debt we need to clean up
/// assert!(result.unwrap().text[0] == "The main function to call which performs the cracking.");

We should instead just return the text without a vector, or we should look at using this vector to store an array of answers for #129