HPCC-10332 Document ToHexPairs & FromHexPairs

Signed-off-by: Jim DeFabia <jamesdefabia@lexisnexis.com>
/*
 * Converts the data value to a sequence of hex pairs.
 *
 * @param value         The data value that should be expanded as a sequence of hex pairs.
 * @return              A string containing a sequence of hex pairs.
 */