tsgo emits incorrect string value when encountering a backslash before a non-special character

## Steps to reproduce

```ts
const enum Currency {
  Euro = "\€",
}

const currency = Currency.Euro;
```

## Behavior with `typescript@6.0`

```js
"use strict";
const currency = "\u20AC" /* Currency.Euro */;
```

## Behavior with `tsgo`

```js
"use strict";
const currency = "\u00E2\uFFFD\uFFFD" /* Currency.Euro */;
```