[docs] set language on FAQ code blocks (sveltejs#7237)

site/content/faq/450-how-do-i-document-my-components.md

@@ -4,7 +4,7 @@ question: How do I document my components?
 
 In editors which use the Svelte Language Server you can document Components, functions and exports using specially formatted comments.
 
-````svelte
+````sv
 <script>
 	/** What should we call the user? */
 	export let name = 'world';

site/content/faq/500-what-about-typescript-support.md

@@ -6,14 +6,14 @@ You need to install a preprocessor such as [svelte-preprocess](https://github.co
 
 To declare the type of a reactive variable in a Svelte template, you should use the following syntax:
 
-```
+```ts
 let x: number;
 $: x = count + 1;
 ```
 
 To import a type or interface make sure to use [TypeScript's `type` modifier](https://www.typescriptlang.org/docs/handbook/release-notes/typescript-3-8.html#type-only-imports-and-export):
 
-```
+```ts
 import type { SomeInterface } from './SomeFile';
 ```