Single letter strings get parsed as italicized in math mode

```
#let q1="q"
#let q2="qq"
$ q q1 q2 "qq" $
```

![image](https://user-images.githubusercontent.com/51149447/227609317-90dc4f6b-15b2-43f7-8119-b4f7f54a55d0.png)

It seems strange to me that `"q"` is rendered the same as `q`. Currently, this can technically be worked around with `"q "`, but that adds a space (not particularly different, but still slightly)