Merge #20238: doc: Missing comments for signet parameters

9c08f3332c doc: Missing comments for signet parameters (kanon)

Pull request description:

  We have such comment in chainparams.cpp. However in Signet the comments are missing.

  In example...

  - Mainnet
  https://github.com/bitcoin/bitcoin/blob/d67883d01e507dd22d1281f4a4860e79d6a46a47/src/chainparams.cpp#L83-L84

  - Testnet
  https://github.com/bitcoin/bitcoin/blob/d67883d01e507dd22d1281f4a4860e79d6a46a47/src/chainparams.cpp#L196-L197

  - Regtest
  https://github.com/bitcoin/bitcoin/blob/d67883d01e507dd22d1281f4a4860e79d6a46a47/src/chainparams.cpp#L392-L393

ACKs for top commit:
  theStack:
    ACK 9c08f3332c

Tree-SHA512: d4e488cf01e50d6320282b29d776c11e6b3d423f9268226749f738a57a51f456b6bd48334d2d5a43afa782df65ea15525a0af1688003c1be6ef915c05650e147

src/chainparams.cpp

@@ -322,8 +322,8 @@ public:
         consensus.nPowTargetSpacing = 10 * 60;
         consensus.fPowAllowMinDifficultyBlocks = false;
         consensus.fPowNoRetargeting = false;
-        consensus.nRuleChangeActivationThreshold = 1916;
-        consensus.nMinerConfirmationWindow = 2016;
+        consensus.nRuleChangeActivationThreshold = 1916; // 95% of 2016
+        consensus.nMinerConfirmationWindow = 2016; // nPowTargetTimespan / nPowTargetSpacing
         consensus.MinBIP9WarningHeight = 0;
         consensus.powLimit = uint256S("00000377ae000000000000000000000000000000000000000000000000000000");
         consensus.vDeployments[Consensus::DEPLOYMENT_TESTDUMMY].bit = 28;