The syntax doesn't get parsed though and just shows up in plain text. Go look at the tag summary right now above the questions, or look at the autocomplete for it in the Ask Question page. You'll see what I mean. I've opted not to edit it further just so you can see this happening (not a huge problem since the tag is only rarely used).
I imagine the best case scenario for the fix would be that we see time-travel this fancy thing. In the autocomplete dropdown it should probably do nothing but look pretty - it could insert the mentioned tag instead, but this could lead to confusion and errors if someone clicks on that box to pick that tag for the suggestion, and accidentally click on a link to another tag mentioned in that description.