[Browser Rendering] add cdp endpoint docs

[meddulla]

Summary

Adds documentation on the new CDP endpoints in Browser Rendering

Screenshots (optional)

Documentation checklist

• Is there a changelog entry (guidelines)? If you don't add one for something awesome and new (however small) — how will our customers find out? Changelogs are automatically posted to RSS feeds, the Discord, and X.
• The change adheres to the documentation style guide.

[ToriLindsay]

Made these updates:

• Code blocks: Added txt language tag to three untagged code blocks in mcp-clients.mdx
• Component: Replaced npm install bash block with PackageManagers component in puppeteer.mdx
• Voice: "We also provide" → "HTTP endpoints are also available" in index.mdx
• Capitalization: "Browser Sessions" → "browser sessions" in index.mdx and mcp-clients.mdx; "Workers binding" → "Workers Bindings" in index.mdx
• Style: Removed "Response:" labels and "5 minutes" → "five minutes" in session-management.mdx
• Frontmatter: Added description to all four docs pages