Improvement of documentation of command line parameter 'whitelist'

Github-Pull: bitcoin#9251
Rebased-From: 8a70a9d

src/init.cpp

@@ -376,7 +376,7 @@ std::string HelpMessage(HelpMessageMode mode)
 #endif
 #endif
     strUsage += HelpMessageOpt("-whitebind=<addr>", _("Bind to given address and whitelist peers connecting to it. Use [host]:port notation for IPv6"));
-    strUsage += HelpMessageOpt("-whitelist=<netmask>", _("Whitelist peers connecting from the given netmask or IP address. Can be specified multiple times.") +
+    strUsage += HelpMessageOpt("-whitelist=<IP address or network>", _("Whitelist peers connecting from the given IP address (e.g. 1.2.3.4) or CIDR notated network (e.g. 1.2.3.0/24). Can be specified multiple times.") +
         " " + _("Whitelisted peers cannot be DoS banned and their transactions are always relayed, even if they are already in the mempool, useful e.g. for a gateway"));
     strUsage += HelpMessageOpt("-whitelistrelay", strprintf(_("Accept relayed transactions received from whitelisted peers even when not relaying transactions (default: %d)"), DEFAULT_WHITELISTRELAY));
     strUsage += HelpMessageOpt("-whitelistforcerelay", strprintf(_("Force relay of transactions from whitelisted peers even if they violate local relay policy (default: %d)"), DEFAULT_WHITELISTFORCERELAY));