#### Fix `prettier-ignore`d `for` initializer (#20204 by @fisker)

<!-- prettier-ignore -->
```jsx
// Input
for (/* prettier-ignore */ let i  = 0; i < 1; i++) {}

// Prettier stable
for (/* prettier-ignore */ let i  = 0;; i < 1; i++) {}

// Prettier main
for (/* prettier-ignore */ let i  = 0; i < 1; i++) {}
```