remove several mentions of list of bytes in predicate descriptions

This is to focus more on the intended core representation of text: In
Prolog, text is ideally represented as a list of characters, and this
is what we want to encourage, especially given Scryer's compact
representation for strings.

For the time being, library(crypto) still also supports lists of bytes in
several predicates. This will likely be removed at some point in the
future. Please use lists of characters to make your code future-proof.

src/prolog/lib/crypto.pl

@@ -155,9 +155,8 @@ crypto_random_byte(B) :- '$crypto_random_byte'(B).
 
    crypto_data_hash(+Data, -Hash, +Options)
 
-   Where Data is a list of bytes (integers between 0 and 255) or
+   Where Data is a list of characters, and Hash is the computed hash
-   characters, and Hash is the computed hash as a list of hexadecimal
+   as a list of hexadecimal characters.
-   characters.
 
    Options is a list of:
 
@@ -231,7 +230,7 @@ hash_algorithm(blake2b512).
    crypto_data_hkdf(+Data, +Length, -Bytes, +Options) is det.
 
    Concentrate possibly dispersed entropy of Data and then expand it
-   to the desired length. Data is a list of bytes or characters.
+   to the desired length. Data is a list of characters.
 
    Bytes is unified with a list of bytes of length Length, and is
    suitable as input keying material and initialization vectors to
@@ -245,7 +244,7 @@ hash_algorithm(blake2b512).
        cryptographically secure algorithm by default.
      - info(+Info)
        Optional context and application specific information,
-       specified as a list of bytes or characters. The default is [].
+       specified as a list of characters. The default is [].
      - salt(+List)
        Optionally, a list of bytes that are used as salt. The
        default is all zeroes.
@@ -480,8 +479,8 @@ bytes_base64_([A,B,C|Ls]) --> [W,X,Y,Z],
    Algorithm, key Key, and initialization vector (or nonce) IV, to
    give CipherText.
 
-   PlainText must be a list of bytes or characters, Key and IV must be
+   PlainText must be a list of characters, Key and IV must be lists of
-   lists of bytes, and CipherText is created as a list of characters.
+   bytes, and CipherText is created as a list of characters.
 
    Keys and IVs can be chosen at random (using for example
    crypto_n_random_bytes/2) or derived from input keying material (IKM)
@@ -579,9 +578,9 @@ crypto_data_encrypt(PlainText0, Algorithm, Key, IV, CipherText, Options) :-
 
    Decrypt the given CipherText, using the symmetric algorithm
    Algorithm, key Key, and initialization vector IV, to give
-   PlainText. CipherText must be a list of bytes or characters, and
+   PlainText. CipherText must be a list of characters, and Key and IV
-   Key and IV must be lists of bytes. PlainText is created as a list
+   must be lists of bytes. PlainText is created as a list of
-   of characters.
+   characters.
 
    Currently, the only supported algorithm is 'chacha20-poly1305',
    a very secure, fast and versatile authenticated encryption method.