A client uses the XTYP_ADVSTOP transaction to end an advise loop with
a server. A Dynamic Data Exchange (DDE) server callback function,
DdeCallback, receives this transaction when a client specifies
XTYP_ADVSTOP in the DdeClientTransaction function.
transactionType - uType - The transaction type.
dataFormat - uFmt - The data format associated with the advise
loop being ended.