feat: add stats/incr/nanmsumabs

[hrshya]

Resolves #5611 .

Description

What is the purpose of this pull request?

This pull request:

• adds stats/incr/nanmsumabs .

Related Issues

Does this pull request have any related issues?

This pull request:

• progresses [RFC]: add incremental accumulators for handling NaN values in stats/incr/* (tracking issue) #5966 .

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.

---

@stdlib-js/reviewers

[stdlib-bot]

Coverage Report

Package	Statements	Branches	Functions	Lines
stats/incr/nanmsumabs	$\color{green}142/142$ $\color{green}+100.00\%$	$\color{green}7/7$ $\color{green}+100.00\%$	$\color{green}2/2$ $\color{green}+100.00\%$	$\color{green}142/142$ $\color{green}+100.00\%$

The above coverage report was generated for the changes in this PR.

[kgryte]

Same comments as other PRs. You'll want to apply similar changes here and elsewhere.