I don't know the term for it (I'm sure someone who does will chime in later), but that still makes sense. It's a way of typing things out how they're pronounced. Some other examples includes: 'at'll (as a shortening of "that'll"), ol' (as a shortening of "old", as in "good ol' boy"), or the most common y'all being a popular southern way of shortening and contracting 'you' and 'all'.
Note that I'm not claiming this is perfect proper English, but just saying that from the perspective of myself being a native speaker, it makes perfect sense to me, and just adds some character to how my mental voice reads their text.