PDBIO.save() include SEQRES information?

### Setup

I have a question regarding Biopython version, Python version, and operating:

```python
Python 3.9.12 (main, Jun 1 2022, 11:38:51)
[GCC 7.5.0] :: Anaconda, Inc. on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import sys; print(sys.version)
3.9.12 (main, Jun 1 2022, 11:38:51)
[GCC 7.5.0]
>>> import platform; print(platform.python_implementation()); print(platform.platform())
CPython
Linux-5.15.0-46-generic-x86_64-with-glibc2.35
>>> import Bio; print(Bio.__version__)
1.79
```

### Question

Hi Biopython developers,

I was wondering with the `PDBIO.save()` method is there any way to include the SEQRES information in the PDB file that is written out? My downstream processes require this information but currently writing out the PDB file with PDBIO does not preserve the SEQRES. May I know if this feature is available?

Thank you.