feat: add constants/float32/min-base2-exponent-subnormal

[gunjjoshi]

Description

What is the purpose of this pull request?

This pull request:

• adds constants/float32/min-base2-exponent-subnormal, which would be the single precision variant for constants/float64/min-base2-exponent-subnormal.
• is a pre-requisite for the single-precision implementation of math/base/special/ldexp.

Related Issues

Does this pull request have any related issues?

This pull request:

• resolves a part of [RFC]: Add C implementations to base special math functions (tracking issue) #649.

Questions

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No.

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No.

Checklist

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• Read, understood, and followed the contributing guidelines.

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@stdlib-js/reviewers

[Planeshifter]

Looks fine (being the single-precision variant of @stdlib/constants/float64/min-base2-exponent-subnormal.)

Value is also correct: The smallest subnormal number In IEEE 754 32-bit floating-point format has an exponent of -126 and a significand of 2^-23, se have 2^(-126) * 2^(-23) = 2^(-149).