A Bad Case: {"story": {""5": "10-10"}}

Output is bad when fixing the following json:
```
from half_json.core import JSONFixer

f = JSONFixer()

invalid_json = """
{"story": {""5": "10-10"}}
""".strip()

f.fix(invalid_json)
```

output result:
```
FixResult(success=True, line='{"story": {"":5,": ":10,"-10":null}}', origin=False)
```

Expected output result:
```
{"story": {"5": "10-10"}}
```