[DO] Binding clarification to Get started for DO

[Oxyjun]

Summary

Closes out https://github.com/cloudflare/cloudflare-docs/pull/16906.

1. Adding helpful link.
2. Editing wording for script_name
3. Adding a bullet point for environment.

Screenshots (optional)

Documentation checklist

• [x] The documentation style guide has been adhered to.
• [ ] If a larger change - such as adding a new page- an issue has been opened in relation to any incorrect or out of date information that this PR fixes.
• [ ] Files which have changed name or location have been allocated redirects.

[cloudflare-workers-and-pages[bot]]

Deploying cloudflare-docs with    Cloudflare Pages

Latest commit:	2977879
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Preview URL:	https://b8278614.cloudflare-docs-7ou.pages.dev
Branch Preview URL:	https://jun-do-get-started-clarifica.cloudflare-docs-7ou.pages.dev

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[github-actions[bot]]

Files with changes (up to 15)

Original Link	Updated Link
https://developers.cloudflare.com/durable-objects/get-started/walkthrough/	https://jun-do-get-started-clarifica.cloudflare-docs-7ou.pages.dev/durable-objects/get-started/walkthrough/

[jldec]

thanks for merging this.