Merge bitcoin/bitcoin#23258: doc: Fix outdated comments referring to ::ChainActive()

BACKPORT NOTE:
changes for TestLockPointValidity in src/validation.cpp are applied to the same function but in src/txmempool.cpp

a0efe529e4fd053b890450413b9ca5e1bcd8f2c2 Fix outdated comments referring to ::ChainActive() (Samuel Dobson)

Pull request description:

  After #21866 there are a few outdated comments referring to `::ChainActive()`, which should instead refer to `ChainstateManager::ActiveChain()`.

ACKs for top commit:
  jamesob:
    ACK a0efe529e4

Tree-SHA512: 80da19c105ed29ac247e6df4c8e916c3bf3f37230b63f07302114eef9c115add673e9649f0bbe237295be0c6da7b1030b5b93e14daf6768f17ce5de7cf2c9ff2

src/index/base.cpp

@@ -331,7 +331,7 @@ bool BaseIndex::BlockUntilSyncedToCurrentChain() const
 
     {
         // Skip the queue-draining stuff if we know we're caught up with
-        // ::ChainActive().Tip().
+        // m_chain.Tip().
         LOCK(cs_main);
         const CBlockIndex* chain_tip = m_chainstate->m_chain.Tip();
         const CBlockIndex* best_block_index = m_best_block_index.load();

src/policy/fees.cpp

@@ -554,7 +554,7 @@ void CBlockPolicyEstimator::processTransaction(const CTxMemPoolEntry& entry, boo
     if (txHeight != nBestSeenHeight) {
         // Ignore side chains and re-orgs; assuming they are random they don't
         // affect the estimate.  We'll potentially double count transactions in 1-block reorgs.
-        // Ignore txs if BlockPolicyEstimator is not in sync with ::ChainActive().Tip().
+        // Ignore txs if BlockPolicyEstimator is not in sync with ActiveChain().Tip().
         // It will be synced next time a block is processed.
         return;
     }

src/txmempool.h

@@ -498,7 +498,7 @@ public:
      * By design, it is guaranteed that:
      *
      * 1. Locking both `cs_main` and `mempool.cs` will give a view of mempool
-     *    that is consistent with current chain tip (`::ChainActive()` and
+     *    that is consistent with current chain tip (`ActiveChain()` and
      *    `CoinsTip()`) and is fully populated. Fully populated means that if the
      *    current active chain is missing transactions that were present in a
      *    previously active chain, all the missing transactions will have been

src/validation.h

@@ -101,7 +101,7 @@ static const bool DEFAULT_SYNC_MEMPOOL = true;
 
 /** Default for -stopatheight */
 static const int DEFAULT_STOPATHEIGHT = 0;
-/** Block files containing a block-height within MIN_BLOCKS_TO_KEEP of ::ChainActive().Tip() will not be pruned. */
+/** Block files containing a block-height within MIN_BLOCKS_TO_KEEP of ActiveChain().Tip() will not be pruned. */
 static const unsigned int MIN_BLOCKS_TO_KEEP = 288;
 static const signed int DEFAULT_CHECKBLOCKS = 6;
 static const unsigned int DEFAULT_CHECKLEVEL = 3;

src/wallet/wallet.cpp

@@ -1366,7 +1366,7 @@ void CWallet::updatedBlockTip()
 void CWallet::BlockUntilSyncedToCurrentChain() const {
     AssertLockNotHeld(cs_wallet);
     // Skip the queue-draining stuff if we know we're caught up with
-    // chainActive.Tip(), otherwise put a callback in the validation interface queue and wait
+    // chain().Tip(), otherwise put a callback in the validation interface queue and wait
     // for the queue to drain enough to execute it (indicating we are caught up
     // at least with the time we entered this function).
     uint256 last_block_hash = WITH_LOCK(cs_wallet, return m_last_block_processed);