fix: support contenteditable binding undefined fallback

.changeset/dry-parrots-bathe.md

@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: support contenteditable binding undefined fallback

packages/svelte/src/internal/client/dom/elements/bindings/universal.js

@@ -18,7 +18,7 @@ export function bind_content_editable(property, element, get_value, update) {
 		var value = get_value();
 
 		if (element[property] !== value) {
-			if (value === null) {
+			if (value == null) {
 				// @ts-ignore
 				var non_null_value = element[property];
 				update(non_null_value);

packages/svelte/tests/runtime-runes/samples/contenteditable-state/Test.svelte

@@ -0,0 +1,9 @@
+<script>
+	let {children} = $props()
+	let innerText = $state()
+	$inspect(innerText);
+</script>
+
+<div contenteditable="true" bind:innerHTML={innerText}>
+	{@render children()}
+</div>

packages/svelte/tests/runtime-runes/samples/contenteditable-state/_config.js

@@ -0,0 +1,5 @@
+import { test } from '../../test';
+
+export default test({
+	html: `<div contenteditable="true">Test</div>`
+});

packages/svelte/tests/runtime-runes/samples/contenteditable-state/main.svelte

@@ -0,0 +1,7 @@
+<script>
+	import Test from './Test.svelte'
+</script>
+
+<Test>
+	Test
+</Test>