fix: improve search input text contrast accessibility

[kartykp]

Summary

• Fix search input text visibility by replacing hardcoded low-contrast input text color with Primer foreground tokens and fallbacks in src/components/text-input.js
• Ensure caret visibility by setting caret-color to the same accessible foreground token
• Improve placeholder readability with muted foreground token fallback and remove opacity fade
• Include required docs formatting update from CI in content/cli/v11/commands/npm-stage.mdx (Prettier only)

Why

• Typed text in the search box could be effectively invisible on light backgrounds, causing an accessibility issue.

Validation

• npx eslint src/components/text-input.js
• npx prettier --check content/cli/v11/commands/npm-stage.mdx

[natalejoe]

Summary

• Fix search input text visibility by replacing hardcoded low-contrast input text color with Primer foreground tokens and fallbacks in src/components/text-input.js
• Ensure caret visibility by setting caret-color to the same accessible foreground token
• Improve placeholder readability with muted foreground token fallback and remove opacity fade
• Include required docs formatting update from CI in content/cli/v11/commands/npm-stage.mdx (Prettier only)

Why

• Typed text in the search cc7a70bd976c5662aa1ca50a6e212c637741e46bcc7a70bd976c5662aa1ca50a6e212c637741e46b could be effectively invisible on light backgrounds, causing an accessibility issue.

Validation

• npx eslint src/components/text-input.js
• npx prettier --check content/cli/v11/commands/npm-stage.mdx