chore: tweak xmlns docs (#12606)

Author: Rich-Harris

documentation/docs/02-template-syntax/09-special-elements.md

@@ -64,7 +64,7 @@ If `this` is the name of a [void element](https://developer.mozilla.org/en-US/do
 <svelte:element this={tag} on:click={handler}>Foo</svelte:element>
 ```
 
-Svelte tries its best to infer the correct namespace from its surroundings, but that's not always possible to analyze statically. You can give a hint by adding a `xmlns` attribute:
+Svelte tries its best to infer the correct namespace from the element's surroundings, but it's not always possible. You can make it explicit with an `xmlns` attribute:
 
 ```svelte
 <svelte:element this={tag} xmlns="http://www.w3.org/2000/svg" />