Rework comment on passThroughOptions

lib/command.js

@@ -1535,9 +1535,10 @@ Expecting one of '${allowedValues.join("', '")}'`);
         }
       }
 
-      // If using passThroughOptions, stop processing options at first command-argument / unknown option.
-      // Processing after an unknown option is not possible because there is no way to know if the next argument is its option-argument and we should continue,
-      // or if it is a command-argument and we should stop.
+      // If using passThroughOptions, stop processing options at first command-argument.
+      // The processing is also stopped when an unknown option is encountered because
+      // - either allowUnknownOption is on and so the option is treated as a command-argument,
+      // - or it is off and so an error will be thrown anyway since no subcommand was found that could reprocess the option.
       if (this._passThroughOptions) {
         dest.push(arg);
         if (args.length > 0) dest.push(...args);