docs: clean up leftover $env references

[teemingc]

Missed a few of these

[pkg-svelte-dev]

Install the latest version of @sveltejs/kit from 0693420:

pnpm add https://pkg.svelte.dev/@sveltejs/kit/c/0693420af6168e3c518f34746b30b16456cf4b4f

Open in pkg.svelte.dev: https://pkg.svelte.dev/repos/kit/pr/16366

[changeset-bot]

⚠️ No Changeset found

Latest commit: 0693420

Merging this PR will not cause a version bump for any packages. If these changes should not result in a new version, you're good to go. If these changes should result in a version bump, you need to add a changeset.

This PR includes no changesets

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[svelte-docs-bot]

Preview: https://svelte-dev-git-preview-kit-16366-svelte.vercel.app/