feat: add math/base/special/acosd

[the-r3aper7]

Resolves #36

Description

What is the purpose of this pull request?

This pull request:

• Adds functionality to compute acosd of any given input.
• Say we have input x, so it should satisfies this x <= 1 or x >= -1 else it will return NaN

input	acosd
0	90
0.5	60
$\frac{1}{\sqrt{2}}$	45
$\frac{\sqrt{3}}{2}$	30
1	0

Related Issues

Does this pull request have any related issues?

This pull request:

• resolves Implement acosd #36
• fixes #

Questions

Any questions for reviewers of this pull request?

No.

Other

Any other information relevant to this pull request? This may include screenshots, references, and/or implementation notes.

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

[the-r3aper7]

@Planeshifter this PR is ready for review.

[Planeshifter]

Will merge after CI has passed; thank you for getting this PR over the finish line!