Expose C distance backend in libmdanalysis.pxd

[hmacdope]

Fixes #4315

Changes made in this Pull Request:

• Refactors C distances to use a PXD
• Expose in libmdanalysis.pxd

PR Checklist

• CHANGELOG updated?
• Issue raised/referenced?

Developers certificate of origin

• I certify that this contribution is covered by the LGPLv2.1+ license as defined in our LICENSE and adheres to the Developer Certificate of Origin.

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📚 Documentation preview 📚: https://mdanalysis--4342.org.readthedocs.build/en/4342/

[github-actions]

Linter Bot Results:

Hi @hmacdope! Thanks for making this PR. We linted your code and found the following:

There are currently no issues detected! 🎉

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (5fa0d27) 93.37% compared to head (baac678) 93.36%.
Report is 7 commits behind head on develop.

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #4342      +/-   ##
===========================================
- Coverage    93.37%   93.36%   -0.01%     
===========================================
  Files          170      184      +14     
  Lines        22295    23433    +1138     
  Branches      4075     4079       +4     
===========================================
+ Hits         20818    21879    +1061     
- Misses         962     1036      +74     
- Partials       515      518       +3     

see 20 files with indirect coverage changes

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[IAlibay]

Thanks @hmacdope.

Only question here is docs - do we have an rst stub or anything where we can document these things? It feels like a loss to have this all be exposed internally but without any information that it exists.

[hmacdope]

@IAlibay good point i'll add a docs page

[IAlibay]

/azp run

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[hmacdope]

@IAlibay turns out we do have a short bit of docs that covers this

[IAlibay]

@IAlibay turns out we do have a short bit of docs that covers this

Thanks for checking, anything that needs updating there for this change?

[hmacdope]

@IAlibay turns out we do have a short bit of docs that covers this

Thanks for checking, anything that needs updating there for this change?

Ah sorry I'm blind, fixed now.

[IAlibay]

Cheers!