Support pydantic field's alias

I suggest to support `pydantic.Field.alias` field. Currently erdantic ignores it.

That's an example with simple `Gift` class:
```python3
from pydantic import BaseModel, Field

class Gift(BaseModel):
for_: str = Field(alias="for")
```

erdantic produces:


Although, pydantic displays a field as `for`:

```python3
>>> Gift.schema()
{'title': 'Gift', 'type': 'object', 'properties': {'for': {'title': 'For', 'type': 'string'}},
'required': ['for']}
```

Libraries like FastAPI use that schema in Swagger generations.

Reproduce the issue with the provided Gift model and compare erdantic's diagram with Pydantic's Gift.schema() output, focusing on Field(alias="for"). Then locate the part of the repository that reads Pydantic model fields and determine how to make the diagram use the alias while preserving a passing test for the example.

Written by the indexing model from the issue text.