chore: fix typos and incorrect test values

[Planeshifter]

Description

What is the purpose of this pull request?

This pull request:

• Fixes duplicate false test cases in array/base/falses type tests to use distinct invalid types (true, false, null)
• Fixes duplicate true test case in array/base/trues type tests replacing it with null
• Fixes incorrect error message in array/nulls benchmark ("should return a typed array" → "should return an array")
• Fixes grammar typo in ndarray/base/maybe-broadcast-arrays JSDoc ("an ndarrays" → "ndarrays")

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.

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.

This PR was authored with assistance from Claude Code, which identified the typos and incorrect test values.

---

@stdlib-js/reviewers

[stdlib-bot]

Coverage Report

Package	Statements	Branches	Functions	Lines
array/base/falses	$\color{green}85/85$ $\color{green}+100.00%$	$\color{green}3/3$ $\color{green}+100.00%$	$\color{green}1/1$ $\color{green}+100.00%$	$\color{green}85/85$ $\color{green}+100.00%$
array/base/trues	$\color{green}85/85$ $\color{green}+100.00%$	$\color{green}3/3$ $\color{green}+100.00%$	$\color{green}1/1$ $\color{green}+100.00%$	$\color{green}85/85$ $\color{green}+100.00%$
array/nulls	$\color{green}118/118$ $\color{green}+100.00%$	$\color{green}7/7$ $\color{green}+100.00%$	$\color{green}1/1$ $\color{green}+100.00%$	$\color{green}118/118$ $\color{green}+100.00%$
ndarray/base/maybe-broadcast-arrays	$\color{green}183/183$ $\color{green}+100.00%$	$\color{green}8/8$ $\color{green}+100.00%$	$\color{green}1/1$ $\color{green}+100.00%$	$\color{green}183/183$ $\color{green}+100.00%$

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

[kgryte]

LGTM.