Add symbol/split

[aryan7071]

Resolves #8488

Description

What is the purpose of this pull request?

This pull request implements the RFC proposing the addition of the package symbol/split.
The package is designed to match the structure and conventions used by existing symbol packages in stdlib, including:

-symbol/has-instance
-symbol/iterator
-symbol/async-iterator
-symbol/is-concat-spreadable

The primary purpose of this package is to export Symbol.split when it exists in the environment, and null otherwise.

This pull request:

-Adds the new @stdlib/symbol/split package
-Renames and adapts code from an existing symbol package template
-Ensures all references use the correct package name (split)
-Creates a variable name consistent with stdlib conventions (e.g., SplitSymbol)
-Provides updated documentation, descriptions, and examples using MDN reference behavior
-Implements tests, benchmarks, and examples for the new package
-Verifies the package follows all project conventions and patterns
-Updates the copyright years to 2025
-Reviews the implementation to ensure there are no copy-paste mistakes

Related Issues

Does this pull request have any related issues?

This pull request has the following related issues:

• [RFC]: add symbol/split #8488

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.

AI Assistance

When authoring the changes proposed in this PR, did you use any kind of AI assistance?

• Yes
• No

If you answered "yes" above, how did you use AI assistance?

• Code generation (e.g., when writing an implementation or fixing a bug)
• Test/benchmark generation
• Documentation (including examples)
• Research and understanding

Disclosure

If you answered "yes" to using AI assistance, please provide a short disclosure indicating how you used AI assistance.

I used ChatGPT to assist with understanding stdlib package structure and documentation conventions.
All final code, edits, and documentation were authored manually and reviewed by me before submission.

---

@stdlib-js/reviewers

[stdlib-bot]

Coverage Report

Package	Statements	Branches	Functions	Lines
symbol/split	$\color{green}101/101$ $color{green}+100.00%$	$\color{red}2/3$ $color{green}+66.67%$	$\color{green}0/0$ $color{green}+100.00%$	$\color{green}101/101$ $color{green}+100.00%$

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

[aryan7071]

This time, I took the time to thoroughly understand the package structure, naming conventions, and documentation patterns used across existing stdlib packages. After reviewing similar implementations, I made the required changes manually and relied on AI only minimally ,mainly for clarification, not generation.