If the user has this rule enabled in their `tsconfig.json`, indexing into objects and arrays will behave differently from how you expect.

```ts
const obj: Record<string, string> = {};

// With noUncheckedIndexedAccess, value will
// be `string | undefined`
// Without it, value will be `string`
const value = obj.key;
```

```ts
const arr: string[] = [];

// With noUncheckedIndexedAccess, value will
// be `string | undefined`
// Without it, value will be `string`
const value = arr[0];
```
