scripted-diff: Rename CBlockTreeDB -> BlockTreeDB

-BEGIN VERIFY SCRIPT-
 sed -i 's|CBlockTreeDB|BlockTreeDB|g' $( git grep -l CBlockTreeDB )
-END VERIFY SCRIPT-

src/node/chainstate.cpp

@@ -37,10 +37,10 @@ static ChainstateLoadResult CompleteChainstateInitialization(
     const ChainstateLoadOptions& options) EXCLUSIVE_LOCKS_REQUIRED(::cs_main)
 {
     auto& pblocktree{chainman.m_blockman.m_block_tree_db};
-    // new CBlockTreeDB tries to delete the existing file, which
+    // new BlockTreeDB tries to delete the existing file, which
     // fails if it's still open from the previous loop. Close it first:
     pblocktree.reset();
-    pblocktree = std::make_unique<CBlockTreeDB>(DBParams{
+    pblocktree = std::make_unique<BlockTreeDB>(DBParams{
         .path = chainman.m_options.datadir / "blocks" / "index",
         .cache_bytes = static_cast<size_t>(cache_sizes.block_tree_db),
         .memory_only = options.block_tree_db_in_memory,