Add array with CRC extra values to detect incompatible XML changes

def generate_message_crc_extra_array(outf, msgs):
    """Add array with CRC extra values to detect incompatible XML changes"""

    crcs = []
    for msg in msgs:
        crcs.append("%u: %u" % (msg.id, msg.crc_extra))

    t.write(outf, """


/**
    Message CRSs extra for detection incompatible XML changes
*/
private let messageCrcsExtra: [UInt8: UInt8] = [${ARRAY_CONTENT}]
""", {'ARRAY_CONTENT' : ", ".join(crcs)})