docs: mention non-Deno Deploy SvelteKit adapters

[fibibot]

Summary

• Adds a short note to the SvelteKit tutorial for users who are not deploying to Deno Deploy or another Deno-compatible platform.
• Links those users to the SvelteKit adapter documentation at https://svelte.dev/docs/kit/adapters.

Fixes #2893
Closes bartlomieju/orchid-inbox#119

Verification

• deno fmt --check
• deno task test
• Confirmed the new link points to https://svelte.dev/docs/kit/adapters.

I also attempted a Lume render with SKIP_REFERENCE=1 BUILD_TYPE=FULL, but this VM is running Deno canary 2.7.14+2d3f3f1 and the build failed on an unrelated MDX lume/jsx-runtime resolution error before reaching this page.