Add help-console command to Qt debug console

- Added `help-console` to the list of autocompletion strings
     - Implemented requested changes to help message:
       - Added an example that uses access-by-index `getblock(getblockhash(0) true)[tx][0]`
       - Replace "bracketed syntax" to "parenthesized syntax" where applicable
       - Replace "separate" with "delimit"
       - Removed `<br>` and `<b>help/help-console</b>` from translation strings, since these parts don't change between languages
       - Changed examples to be based off `getblock 0` so they will work even with pruned/no blockchain and `disablewallet` if copied and pasted
       - Clarified syntax for queries of named/unnamed result objects.

src/qt/rpcconsole.cpp

@@ -392,11 +392,37 @@ void RPCExecutor::request(const QString &command)
     {
         std::string result;
         std::string executableCommand = command.toStdString() + "\n";
+
+        // Catch the console-only-help command before RPC call is executed and reply with help text as-if a RPC reply.
+        if(executableCommand == "help-console\n")
+        {
+            Q_EMIT reply(RPCConsole::CMD_REPLY, QString(("\n"
+                "This console accepts RPC commands using the standard syntax.\n"
+                "   example:    getblockhash 0\n\n"
+
+                "This console can also accept RPC commands using parenthesized syntax.\n"
+                "   example:    getblockhash(0)\n\n"
+
+                "Commands may be nested when specified with the parenthesized syntax.\n"
+                "   example:    getblock(getblockhash(0) 1)\n\n"
+
+                "A space or a comma can be used to delimit arguments for either syntax.\n"
+                "   example:    getblockhash 0\n"
+                "               getblockhash,0\n\n"
+
+                "Named results can be queried with a non-quoted key string in brackets.\n"
+                "   example:    getblock(getblockhash(0) true)[tx]\n\n"
+
+                "Results without keys can be queried using an integer in brackets.\n"
+                "   example:    getblock(getblockhash(0),true)[tx][0]\n\n")));
+            return;
+        }
         if(!RPCConsole::RPCExecuteCommandLine(result, executableCommand))
         {
             Q_EMIT reply(RPCConsole::CMD_ERROR, QString("Parse error: unbalanced ' or \""));
             return;
         }
+
         Q_EMIT reply(RPCConsole::CMD_REPLY, QString::fromStdString(result));
     }
     catch (UniValue& objError)
@@ -645,6 +671,7 @@ void RPCConsole::setClientModel(ClientModel *model)
             wordList << ("help " + commandList[i]).c_str();
         }
 
+        wordList << "help-console";
         wordList.sort();
         autoCompleter = new QCompleter(wordList, this);
         autoCompleter->setModelSorting(QCompleter::CaseSensitivelySortedModel);
@@ -750,10 +777,11 @@ void RPCConsole::clear(bool clearHistory)
 	 
     message(CMD_REPLY, (tr("Welcome to the %1 RPC console.").arg(tr(PACKAGE_NAME)) + "<br>" +
                         tr("Use up and down arrows to navigate history, and %1 to clear screen.").arg("<b>"+clsKey+"</b>") + "<br>" +
-                        tr("Type <b>help</b> for an overview of available commands.")) +
-                        "<br><span class=\"secwarning\">" +
+                        tr("Type %1 for an overview of available commands.").arg("<b>help</b>") + "<br>" +
+                        tr("For more information on using this console type %1.").arg("<b>help-console</b>") +
+                        "<br><span class=\"secwarning\"><br>" +
                         tr("WARNING: Scammers have been active, telling users to type commands here, stealing their wallet contents. Do not use this console without fully understanding the ramifications of a command.") +
-                        "</span>",
+                        "</span>"),
                         true);
 }