The Morningstars description is super dated, something I noticed while looking over the descriptions myself (e: after the last release, mind you), and the reference to fighter support relates to a much earlier release (e: of Starsector).
While flight decks greatly enhanced your ability to support fighter craft, your actual support capacity for fighters was related to a fighter support quantity which was a stat each ship had (though in most cases this amount was 0) which represented the total FP cost in fighters that ship could provide logistical support for, and you could repair and replace fighter frames as long as the number was under that total, regardless of whether you had flight decks or not.
The Morningstar was among those craft which added to FP support, but it has never had a flight deck.
Though if you didn't have flight decks the rate of repair was painfully--if not agonizingly--slow. Ultimately the mechanic got nixed and the game is better for it.
Also, as JohnDoe noted, the Morningstar is a pretty powerful small destroyer regardless, and it certainly doesn't need a flight deck.