docs: replace N-ary times `⨉` with multiplication sign `×` (#18418)

Replaces the incorrect N-Ary Times Operator `⨉` (U+2A09) with the
correct Multiplication Sign `×` (U+00D7) in the box dimension label.
Former is intended for mathematical set theory and type theory contexts.
For physical dimensions (width × height), `×` is the correct symbol.

documentation/docs/03-template-syntax/11-declaration-tags.md

@@ -13,7 +13,7 @@ Declaration tags define local variables inside markup with `const` or `let`:
 
 {#each boxes as box}
 	{const area = box.width * box.height}
-	{const label = `${box.width} ⨉ ${box.height} = ${area}`}
+	{const label = `${box.width} × ${box.height} = ${area}`}
 
 	<p>{label}</p>
 {/each}