convert latex to unicode before sluggifying

[linuxrider]

Checklist

• Added an entry in doc/news/.
• Added a test for this change.
• Updated the documentation.

[DunklesArchipel]

In echemdb/electrochemistry-data#68 I have now a method that simply replaces all non utf-8 characters in the entire bibtex entry, such that we omit further issues when these entries are used. Maybe we want to do that with the bibtex key that we download?

[linuxrider]

This is what we get from the api.

@article{Herrero_2001,
  title={Underpotential Deposition at Single Crystal Surfaces of Au, Pt, Ag and Other Materials},
  volume={101},
  ISSN={1520-6890},
  url={http://dx.doi.org/10.1021/cr9600363},
  DOI={10.1021/cr9600363},
  number={7},
  journal={Chemical Reviews},
  publisher={American Chemical Society (ACS)},
  author={Herrero, Enrique and Buller, Lisa J. and Abruña, Héctor D.},
  year={2001},
  month=jun,
  pages={1897–1930}
}

And this from the journal website.

@article{doi:10.1021/cr9600363,
author = {Herrero, Enrique and Buller, Lisa J. and Abru{\~n}a, H{\'e}ctor D.},
title = {Underpotential Deposition at Single Crystal Surfaces of Au, Pt, Ag and Other Materials},
journal = {Chemical Reviews},
volume = {101},
number = {7},
pages = {1897-1930},
year = {2001},
doi = {10.1021/cr9600363},
    note ={PMID: 11710235},

URL = { 
    
        https://doi.org/10.1021/cr9600363
    
    

},
eprint = { 
    
        https://doi.org/10.1021/cr9600363
    
    

}

}