mining: Improve `-blockmaxcost` help message

One-word replacement to #8354.

src/init.cpp

@@ -452,7 +452,7 @@ std::string HelpMessage(HelpMessageMode mode)
     strUsage += HelpMessageOpt("-mempoolreplacement", strprintf(_("Enable transaction replacement in the memory pool (default: %u)"), DEFAULT_ENABLE_REPLACEMENT));
 
     strUsage += HelpMessageGroup(_("Block creation options:"));
-    strUsage += HelpMessageOpt("-blockmaxcost=<n>", strprintf(_("Set maximum block cost (default: %d)"), DEFAULT_BLOCK_MAX_COST));
+    strUsage += HelpMessageOpt("-blockmaxcost=<n>", strprintf(_("Set maximum BIP141 block cost (default: %d)"), DEFAULT_BLOCK_MAX_COST));
     strUsage += HelpMessageOpt("-blockmaxsize=<n>", strprintf(_("Set maximum block size in bytes (default: %d)"), DEFAULT_BLOCK_MAX_SIZE));
     strUsage += HelpMessageOpt("-blockprioritysize=<n>", strprintf(_("Set maximum size of high-priority/low-fee transactions in bytes (default: %d)"), DEFAULT_BLOCK_PRIORITY_SIZE));
     if (showDebug)