[doc] correct comment about ATMPW

ATMPW stands for AcceptToMemoryPoolWorker, which was removed in bitcoin#16400.

src/validation.cpp

@@ -1100,7 +1100,7 @@ static MempoolAcceptResult AcceptToMemoryPoolWithTime(const CChainParams& chainp
     assert(std::addressof(::ChainstateActive()) == std::addressof(active_chainstate));
     const MempoolAcceptResult result = MemPoolAccept(pool, active_chainstate).AcceptSingleTransaction(tx, args);
     if (result.m_result_type != MempoolAcceptResult::ResultType::VALID) {
-        // Remove coins that were not present in the coins cache before calling ATMPW;
+        // Remove coins that were not present in the coins cache before MemPoolAccept;
         // this is to prevent memory DoS in case we receive a large number of
         // invalid transactions that attempt to overrun the in-memory coins cache
         // (`CCoinsViewCache::cacheCoins`).