oxfmt inserts a stray space before [index] in CSS theme() values

oxfmt 0.58.0

In a `.css` file, oxfmt space-separates the `[0]` array index in a Tailwind `theme()` call (it seems to treat `[0]` like an attribute selector). The result is invalid — Tailwind then errors with `'fontSize.af-md [0]' does not exist`.

**Before:**

```css
p {
  font-size: theme(fontSize.af-md[0]);
}
```

**After (`oxfmt`):**

```css
p {
  font-size: theme(fontSize.af-md [0]);
}
```