Putting two spaces before the line formats is as code.

Example:

No space before start of line.

One space before start of line.

  Two spaces before start of line.

Thus, you can put multiple lines of code with indentation as well as long as you put two spaces at the start of the line:

int main() { return 0; }

  int main() {
    return 0;
  }

See https://news.ycombinator.com/formatdoc