I've used Drupal for years and I've even posted issues or comments in the issue queue on Drupal.org. One thing that always alluded me was the ability to color link another node issue. I knew there was some sort of magic way to do it, but I had no idea how until someone updated my issue post with a link to the parent issue, over to the automagic colored link with title.
It's actually quite simple:
This is usually the number in the URL, for example: https://www.drupal.org/node/2830239
The issue # is 2830239
Once you have the issue number, simply bracket it with a pound symbol in front:
Add that format to link to any other issue body or comment and the drupal.org site will automagically convert it for you.
I suppose I should have looked for it, but I just didn't feel like digging for it. Drupal is known for some pretty awesome stuff, but user friendliness isn't one of them.