fix: add missing comment change from bitcoin#24187

Adds missing trivial comment change from commit 5179656:
- Update comment in GetStateStatisticsFor from 'Find beginning of period'
  to 'Find how many blocks are in the current period'

This change was part of the original Bitcoin PR but was missing from the
Dash backport, causing scope validation issues.

Also removes Bitcoin-specific functionality that doesn't exist in Dash:
- Remove DEPLOYMENT_SEGWIT and DEPLOYMENT_TAPROOT references
- Remove unregistered getdeploymentinfo function that contains Bitcoin-specific deployments
- Remove associated documentation for features not implemented in Dash

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: Claude Code

doc/release-notes-24187.md

@@ -1455,7 +1455,6 @@ static void SoftForkDescPushBack(const CBlockIndex* blockindex, const std::unord
 
 namespace {
 /* TODO: when -deprecatedrpc=softforks is removed, drop these */
-UniValue DeploymentInfo(const CBlockIndex* tip, const Consensus::Params& consensusParams);
 extern const std::vector<RPCResult> RPCHelpForDeployment;
 }
 
@@ -1619,68 +1618,8 @@ const std::vector<RPCResult> RPCHelpForDeployment{
     }},
 };
 
-UniValue DeploymentInfo(const CBlockIndex* blockindex, const Consensus::Params& consensusParams)
-{
-    UniValue softforks(UniValue::VOBJ);
-    std::unordered_map<uint8_t, int> signals{};  // Empty signals map for now
-    // Buried deployments
-    SoftForkDescPushBack(blockindex, softforks, consensusParams, Consensus::DEPLOYMENT_HEIGHTINCB);
-    SoftForkDescPushBack(blockindex, softforks, consensusParams, Consensus::DEPLOYMENT_DERSIG);
-    SoftForkDescPushBack(blockindex, softforks, consensusParams, Consensus::DEPLOYMENT_CLTV);
-    SoftForkDescPushBack(blockindex, softforks, consensusParams, Consensus::DEPLOYMENT_CSV);
-    SoftForkDescPushBack(blockindex, softforks, consensusParams, Consensus::DEPLOYMENT_SEGWIT);
-    // BIP9 deployments
-    SoftForkDescPushBack(blockindex, signals, softforks, consensusParams, Consensus::DEPLOYMENT_TESTDUMMY);
-    SoftForkDescPushBack(blockindex, signals, softforks, consensusParams, Consensus::DEPLOYMENT_TAPROOT);
-    return softforks;
-}
 } // anon namespace
 
-static RPCHelpMan getdeploymentinfo()
-{
-    return RPCHelpMan{"getdeploymentinfo",
-        "Returns an object containing various state info regarding deployments of consensus changes.",
-        {
-            {"blockhash", RPCArg::Type::STR_HEX, RPCArg::Default{"hash of current chain tip"}, "The block hash at which to query deployment state"},
-        },
-        RPCResult{
-            RPCResult::Type::OBJ, "", "", {
-                {RPCResult::Type::STR, "hash", "requested block hash (or tip)"},
-                {RPCResult::Type::NUM, "height", "requested block height (or tip)"},
-                {RPCResult::Type::OBJ, "deployments", "", {
-                    {RPCResult::Type::OBJ, "xxxx", "name of the deployment", RPCHelpForDeployment}
-                }},
-            }
-        },
-        RPCExamples{ HelpExampleCli("getdeploymentinfo", "") + HelpExampleRpc("getdeploymentinfo", "") },
-        [&](const RPCHelpMan& self, const JSONRPCRequest& request) -> UniValue
-        {
-            const ChainstateManager& chainman = EnsureAnyChainman(request.context);
-            LOCK(cs_main);
-            const CChainState& active_chainstate = chainman.ActiveChainstate();
-
-            const CBlockIndex* blockindex;
-            if (request.params[0].isNull()) {
-                blockindex = active_chainstate.m_chain.Tip();
-                CHECK_NONFATAL(blockindex);
-            } else {
-                const uint256 hash(ParseHashV(request.params[0], "blockhash"));
-                blockindex = chainman.m_blockman.LookupBlockIndex(hash);
-                if (!blockindex) {
-                    throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, "Block not found");
-                }
-            }
-
-            const Consensus::Params& consensusParams = Params().GetConsensus();
-
-            UniValue deploymentinfo(UniValue::VOBJ);
-            deploymentinfo.pushKV("hash", blockindex->GetBlockHash().ToString());
-            deploymentinfo.pushKV("height", blockindex->nHeight);
-            deploymentinfo.pushKV("deployments", DeploymentInfo(blockindex, consensusParams));
-            return deploymentinfo;
-        },
-    };
-}
 
 /** Comparison function for sorting the getchaintips heads.  */
 struct CompareBlocksByHeight