Sync svelte docs (#1700)

sync svelte docs

Co-authored-by: svelte-docs-bot[bot] <196124396+svelte-docs-bot[bot]@users.noreply.github.com>

Author: github-actions[bot]

apps/svelte.dev/content/docs/svelte/03-template-syntax/03-each.md

@@ -13,7 +13,9 @@ title: {#each ...}
 {#each expression as name, index}...{/each}
 ```
 
-Iterating over values can be done with an each block. The values in question can be arrays, array-like objects (i.e. anything with a `length` property), or iterables like `Map` and `Set` — in other words, anything that can be used with `Array.from`.
+Iterating over values can be done with an each block. The values in question can be arrays, array-like objects (i.e. anything with a `length` property), or iterables like `Map` and `Set`— in other words, anything that can be used with `Array.from`.
+
+If the value is `null` or `undefined`, it is treated the same as an empty array (which will cause [else blocks](#Else-blocks) to be rendered, where applicable).
 
 ```svelte
 <h1>Shopping list</h1>