Add multi-environment type generation documentation / changelog

[NuroDev]

Summary

cloudflare/workers-sdk#11893 fixes a long standing issue with the wrangler types command where only bindings from the top-level were included in the generated Env type (Unless a --env flag was used, by which point it would only include that environments binding types).

However, this is now fixed such that binding types are generated for all environments into one, including top-level bindings.

Documentation checklist

• Is there a changelog entry (guidelines)?
• The change adheres to the documentation style guide.
• If a larger change - such as adding a new page- an issue has been opened in relation to any incorrect or out of date information that this PR fixes.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.

[github-actions]

This pull request requires reviews from CODEOWNERS as it changes files that match the following patterns:

Pattern	Owners
/src/content/changelog/	@cloudflare/pm-changelogs, @cloudflare/pcx-technical-writing
/src/content/docs/workers/wrangler/	@cloudflare/wrangler, @irvinebroque, @cloudflare/pcx-technical-writing

[github-actions]

Preview URL: https://6c945cd3.preview.developers.cloudflare.com
Preview Branch URL: https://nurodev-aggregate-binding-env-types.preview.developers.cloudflare.com

Files with changes (up to 15)

Original Link	Updated Link
https://developers.cloudflare.com/changelog/2026-01-13-wrangler-types-multi-environment/	https://nurodev-aggregate-binding-env-types.preview.developers.cloudflare.com/changelog/2026-01-13-wrangler-types-multi-environment/
https://developers.cloudflare.com/workers/wrangler/commands/	https://nurodev-aggregate-binding-env-types.preview.developers.cloudflare.com/workers/wrangler/commands/