Fix product name in the error message for invalid commands.

$ bazel blah
Command 'blah' not found. Try 'bazel help'.

--
MOS_MIGRATED_REVID=95089307

src/main/java/com/google/devtools/build/lib/runtime/BlazeCommandDispatcher.java

@@ -296,7 +296,8 @@ public int exec(List<String> args, OutErr originalOutErr, long firstContactTime)
 
     BlazeCommand command = commandsByName.get(commandName);
     if (command == null) {
-      outErr.printErrLn("Command '" + commandName + "' not found. " + "Try 'blaze help'.");
+      outErr.printErrLn(String.format(
+          "Command '%s' not found. Try '%s help'.", commandName, Constants.PRODUCT_NAME));
       return ExitCode.COMMAND_LINE_ERROR.getNumericExitCode();
     }
     Command commandAnnotation = command.getClass().getAnnotation(Command.class);