Use picocolors instead of supports-color

[sdotson]

PR Checklist

• Addresses an existing open issue: fixes 🚀 Feature: Remove supports-color now that we have picocolors #5470
• That issue was marked as status: accepting prs
• Steps in CONTRIBUTING.md were taken

Overview

Summary

Removes the supports-color dependency in favor of using picocolors' built-in isColorSupported property, which provides the same functionality.

Changes

• Replaced require('supports-color') with require('picocolors') in lib/reporters/base.js
• Updated color detection logic from supportsColor.stdout to pc.isColorSupported
• Removed supports-color from production dependencies in package.json
• Removed browser shim for supports-color from package.json browser field

Motivation

This change reduces unnecessary dependencies by leveraging functionality already available in picocolors, which Mocha already depends on. The isColorSupported property from picocolors provides the
same color detection capability as supports-color, making the separate dependency redundant.

Fixes #5470

[valadaptive]

I already have a PR for this (though I forgot to remove the browser shim from package.json). It's blocked on alexeyraspopov/picocolors#96, which is causing some tests to fail.

Moved supports-color to dev dependencies in package-lock.json (still used by some dev dependencies)

I noticed this is in your PR summary but not in the code changes itself. That's good because it's not necessary: if a dependency itself depends on a package, it'll get installed anyway--that's how package managers work. Why is this line in the PR summary?

[sdotson]

I already have a PR for this (though I forgot to remove the browser shim from package.json). It's blocked on alexeyraspopov/picocolors#96, which is causing some tests to fail.

Moved supports-color to dev dependencies in package-lock.json (still used by some dev dependencies)

I noticed this is in your PR summary but not in the code changes itself. That's good because it's not necessary: if a dependency itself depends on a package, it'll get installed anyway--that's how package managers work. Why is this line in the PR summary?

Oh you're right. My mistake. That line is totally unnecessary. Feel free to close this pr if it is a duplicate.

[JoshuaKGoldberg]

Thanks for trying this out either way!