fix: correct private member name _sek to _sep in random/streams/chi

[Planeshifter]

Description

What is the purpose of this pull request?

This pull request:

• corrects a private member name typo in the random/streams/chi TypeScript declaration.

The member documented as the "Data separator" was named _sek:

/**
* Data separator.
*/
private readonly _sek: string;

but the implementation defines and uses _sep:

setNonEnumerableReadOnly( this, '_sep', opts.sep );
// ...
r = string2buffer( this._sep+r );

This corrects _sek to _sep so the declaration matches the implementation.

Related Issues

Does this pull request have any related issues?

No.

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.

Identified during a TypeScript-declaration audit of the @stdlib/random namespace and verified against lib/main.js. The same typo exists in random/streams/t and is addressed in a separate PR.

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

A TypeScript-declaration audit surfaced this issue using Claude Code; the finding was independently verified against the implementation (lib/main.js) and reviewed by myself before submitting.

---

@stdlib-js/reviewers

[stdlib-bot]

Coverage Report

Package	Statements	Branches	Functions	Lines
random/streams/chi	$\color{green}812/812$ $\color{green}+100.00\%$	$\color{green}92/92$ $\color{green}+100.00\%$	$\color{green}15/15$ $\color{green}+100.00\%$	$\color{green}812/812$ $\color{green}+100.00\%$

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