docs: update boost version in math/base/special/digamma

[gunjjoshi]

Description

What is the purpose of this pull request?

This pull request:

• addresses the changes discussed in feat: add C implementation for math/base/special/digamma #2533.
• updates boost link in main.c and main.js, in math/base/special/digamma, from 1.53 to 1.85.
• earlier we had the link to the documentation of the implementation, I have replaced it with the link to the actual implementation of the latest version.

Related Issues

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None.

Questions

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No.

Other

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I checked out both the implementations, but couldn't find any change, instead of some documentation changes. The function digamma_imp(T x, const Tag* t, const Policy& pol) is the same in both of them.

• 1.53: https://www.boost.org/doc/libs/1_53_0/boost/math/special_functions/digamma.hpp
• 1.85: https://www.boost.org/doc/libs/1_85_0/boost/math/special_functions/digamma.hpp

I might be mistaken regarding this, but it would be great if you can also have a look at it once, if there are any significant changes, as boost implementations are quite confusing.

Checklist

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• Read, understood, and followed the contributing guidelines.

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@stdlib-js/reviewers

[Planeshifter]

@gunjjoshi Thanks for double-checking the implementations. I believe you are correct and that there are indeed no applicable changes between the versions; I got confused too, it seems.