Merge bitcoin/bitcoin#26965: refactor: Remove stray cs_main redundant declaration

faba08b5b4 refactor: Remove stray cs_main redundant declaration (MarcoFalke)
fa02591edf doc: Export threadsafety.h from sync.h (MarcoFalke)

Pull request description:

  Looks like this was forgotten when introducing kernel/cs_main ?

  Also, there is a commit to export threadsafety.h from sync.h.

ACKs for top commit:
  hebasto:
    ACK faba08b5b4

Tree-SHA512: 0aa58e7693b6fcd504f9da7339f8baa463a6407f67b27f68002db705f4642321ac3765f16c3d906c925ee24085591b79160a62fa5f4aaf6f2e5dcc788411800d

ci/test/06_script_b.sh

@@ -48,6 +48,7 @@ if [ "${RUN_TIDY}" = "true" ]; then
           " src/node/chainstate.cpp"\
           " src/node/chainstatemanager_args.cpp"\
           " src/node/mempool_args.cpp"\
+          " src/node/utxo_snapshot.cpp"\
           " src/node/validation_cache_args.cpp"\
           " src/policy/feerate.cpp"\
           " src/policy/packages.cpp"\