feat: add C implementation for math/base/special/betainc

[Neerajpathak07]

Progresses #649
Resolves #3423

Description

What is the purpose of this pull request?

This pull request:

• adds C implementation for math/base/special/betainc

Related Issues

Does this pull request have any related issues?

This pull request:

• progresses [RFC]: Add C implementations to base special math functions (tracking issue) #649

• resolves [RFC]: Add C implementation for @stdlib/stats/base/dists/beta/cdf #3423

Questions

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No.

Other

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No.

Checklist

Please ensure the following tasks are completed before submitting this pull request.

• Read, understood, and followed the contributing guidelines

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@stdlib-js/reviewers

[Neerajpathak07]

This PR will need the C implementation for math/base/special/kernel-betainc to be merged to develop.

[Neerajpathak07]

Reference:-