message: Update help text for -checkblockindex
  Remove the text 'Also sets -checkmempool' from the -checkblockindex help
  text, since that is not the case.
diff: @@ -343,7 +343,7 @@ static void addDebuggingOptions(AllowedArgs& allowedArgs, HelpMessageMode mode)
  allowedArgs
  .addHeader(_("Debugging/Testing options:"))
  .addArg("uacomment=<cmt>", requiredStr, _("Append comment to the user agent string"))
  - .addDebugArg("checkblockindex", optionalBool, strprintf("Do a full consistency check for mapBlockIndex, setBlockIndexCandidates, chainActive and mapBlocksUnlinked occasionally. Also sets -checkmempool (default: %u)", false))
  + .addDebugArg("checkblockindex", optionalBool, strprintf("Do a full consistency check for mapBlockIndex, setBlockIndexCandidates, chainActive and mapBlocksUnlinked occasionally (default: %u)", false))
  .addDebugArg("checkmempool=<n>", requiredInt, strprintf("Run checks every <n> transactions (default: %u)", false))
  .addDebugArg("checkpoints", optionalBool, strprintf("Disable expensive verification for known chain history (default: %u)", DEFAULT_CHECKPOINTS_ENABLED))
  #ifdef ENABLE_WALLET
  