changed btype, to btype as its causing error while running tests

[saiudayagiri]

As this is a small change i have not raised any issue.

Changes made in this Pull Request:

• Fixed the parameter name in pytest.mark.parametrize for test_VE in testsuite/MDAnalysisTests/core/test_atomgroup.py.
• Removed the unintended trailing comma from "btype,", changing it to "btype" so that the parametrized argument correctly matches the test function signature.

LLM / AI generated code disclosure

LLMs or other AI-powered tools (beyond simple IDE use cases) were used in this contribution: No

PR Checklist

• Issue raised/referenced?
• Tests updated/added?
• Documentation updated/added?
• package/CHANGELOG file updated?
• Is your name in package/AUTHORS? (If it is not, add it!)
• LLM/AI disclosure was updated.

Developers Certificate of Origin

I certify that I can submit this code contribution as described in the [Developer Certificate of Origin](https://developercertificate.org/), under the MDAnalysis [LICENSE](https://github.com/MDAnalysis/mdanalysis/blob/develop/LICENSE).

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 93.85%. Comparing base (941d679) to head (19e65a6).
⚠️ Report is 1 commits behind head on develop.

Additional details and impacted files

@@           Coverage Diff            @@
##           develop    #5401   +/-   ##
========================================
  Coverage    93.85%   93.85%           
========================================
  Files          182      182           
  Lines        22509    22509           
  Branches      3202     3202           
========================================
+ Hits         21125    21126    +1     
+ Misses         922      921    -1     
  Partials       462      462           

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[saiudayagiri]

@IAlibay, could you please take a look at this?

Also, I noticed that a large number of files are currently failing formatting checks. I tried running Black across the entire project locally, which resolved formatting issues in around 264 files. I have already committed those changes to a separate branch.

If a repository-wide formatting update would be useful and aligns with the project's expectations, please let me know and I can open a separate PR for those changes.

[RMeli]

@saiudayagiri as far as I can see, only one file is failing the formatting check:

would reformat /home/runner/work/mdanalysis/mdanalysis/testsuite/MDAnalysisTests/coordinates/test_tpr.py

I think this was introduced in #5372 and seems to have been fixed in #5374 already. You should be able to just merge the changes on develop to fix this.