add comment to HelpMessage() to ensure alphabetical ordering

- also rename hmm to mode, to be consistent between .h and .cpp

src/init.cpp

@@ -195,8 +195,9 @@ bool static Bind(const CService &addr, unsigned int flags) {
     return true;
 }
 
-std::string HelpMessage(HelpMessageMode hmm)
+std::string HelpMessage(HelpMessageMode mode)
 {
+    // When adding new options to the categories, please keep and ensure alphabetical ordering.
     string strUsage = _("Options:") + "\n";
     strUsage += "  -?                     " + _("This help message") + "\n";
     strUsage += "  -alertnotify=<cmd>     " + _("Execute command when a relevant alert is received or we see a really long fork (%s in cmd is replaced by message)") + "\n";
@@ -204,7 +205,7 @@ std::string HelpMessage(HelpMessageMode hmm)
     strUsage += "  -checkblocks=<n>       " + _("How many blocks to check at startup (default: 288, 0 = all)") + "\n";
     strUsage += "  -checklevel=<n>        " + _("How thorough the block verification of -checkblocks is (0-4, default: 3)") + "\n";
     strUsage += "  -conf=<file>           " + _("Specify configuration file (default: bitcoin.conf)") + "\n";
-    if (hmm == HMM_BITCOIND)
+    if (mode == HMM_BITCOIND)
     {
 #if !defined(WIN32)
         strUsage += "  -daemon                " + _("Run in the background as a daemon and accept commands") + "\n";
@@ -278,7 +279,7 @@ std::string HelpMessage(HelpMessageMode hmm)
     strUsage += "                         " + _("If <category> is not supplied, output all debugging information.") + "\n";
     strUsage += "                         " + _("<category> can be:");
     strUsage +=                                 " addrman, alert, coindb, db, lock, rand, rpc, selectcoins, mempool, net"; // Don't translate these and qt below
-    if (hmm == HMM_BITCOIN_QT)
+    if (mode == HMM_BITCOIN_QT)
         strUsage += ", qt";
     strUsage += ".\n";
     strUsage += "  -gen                   " + _("Generate coins (default: 0)") + "\n";