[1.9.x] Fixed a typo in auth docs.

    that ``bcrypt(password_with_100_chars) == bcrypt(password_with_100_chars[:72])``.

    The original ``BCryptPasswordHasher`` does not have any special handling and

    thus is also subject to this hidden password length limit.

    ``BCryptSHA256PasswordHasher`` fixes this by first first hashing the

    ``BCryptSHA256PasswordHasher`` fixes this by first hashing the

    password using sha256. This prevents the password truncation and so should

    be preferred over the ``BCryptPasswordHasher``. The practical ramification

    of this truncation is pretty marginal as the average user does not have a