why module name judge like this?

**Describe the bug**

Version: 21.0.1

sourceText:
```typescript
declare module '@x/y' {};
```

judge:
```typescript
const modules = sourceFile.getModules();

modules.forEach(m => {
if (m.getName() === "'@x/y'") {
console.log('enter');
}
});
```
so, Why ? "'@x/y'" instead of '@x/y'?

And:
```ts
const t = sourceFile.getModule('@x/y'); // => undefined ?
const t = sourceFile.getModule("'@x/y'"); // => it works...
```
**Expected behavior**
'@x/y'