improve README examples of array/base/assert namespace

[soumajit23]

Resolves # 1545

Description

What is the purpose of this pull request?

This pull request:

• improves the README examples of array/base/assert namespace
• updates the examples/index.js file

Related Issues

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This pull request:

• resolves #
• fixes #

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Other

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• Read, understood, and followed the contributing guidelines.

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@stdlib-js/reviewers

[soumajit23]

@Planeshifter hello,
could you please review it?