docs(fix): example text unescaped entities (#57255)
Fix bug in example code. Loading with `'` can not be built with the default ESLint rules:
```ssh
./src/app/reviews/loading.tsx
4:15 Error: `'` can be escaped with `'`, `‘`, `'`, `’`. react/no-unescaped-entities
4:26 Error: `'` can be escaped with `'`, `‘`, `'`, `’`. react/no-unescaped-entities
```
