bibtex: add trailing comma in url field

[alejandromumo]

The output of a bibtex export is wrong right now. Note the field url does not have a comma in the end:

@software{daniel_hay_guest_2024_14276439,
  author       = {Daniel Hay Guest and
                  Joshua Wyatt Smith and
                  Michela Paganini and
                  Michael Kagan and
                  Marie Lanfermann and
                  Attila Krasznahorkay and
                  Daniel Edison Marley and
                  Aishik Ghosh and
                  Benjamin Huth and
                  Matthew Feickert},
  title        = {lwtnn/lwtnn: v2.14.1},
  month        = dec,
  year         = 2024,
  publisher    = {Zenodo},
  version      = {v2.14.1},
  doi          = {10.5281/zenodo.14276439},
  url          = {https://doi.org/10.5281/zenodo.14276439}
  swhid        = {swh:1:dir:e8e8cd6fad6becd5e8b193c1148f94e023df3bae
                   ;origin=https://doi.org/10.5281/zenodo.597221;visi
                   t=swh:1:snp:fe7e271159192d7ee02e85798322462a200620
                   a1;anchor=swh:1:rel:698f80ceb7827b6d852a1bbf695eaf
                   b0fccc5079;path=/
                  },
}

[tmorrell]

I think the last item shouldn't have a comma. Maybe strip the last entry in parse_fields? I'm not exactly sure how it works with the mixins though.

[ptamarit]

I think the last item shouldn't have a comma. Maybe strip the last entry in parse_fields? I'm not exactly sure how it works with the mixins though.

Several existing tests in test_bibtex_serializer.py have a trailing comma, so it might be fine.
But I agree that it's probably better to be conservative in what we produce and remove the trailing space (if not too difficult).

[slint]

I tried to import in Zotero examples with and without the trailing commas (even in fields in the "middle"), and things seem to work. In general, I feel the best way to test, is to try with existing 3rd-party tools that accept BibTex as input 😅

Given how messy BibTex has been, and sort of in between this weird human/machine-readable uncanny zone, I feel that having trailing commas for all fields should be fine.

[tmorrell]

Sounds fine, once tests pass.

[slint]

Merging, since I only see JS tests failing for ESlint