fix: add h3 in src/guide/typescript/composition-api.md (#1627)

* Update ssr.md

* Update composition-api.md

* Update ssr.md

* Update src/guide/typescript/composition-api.md

Co-authored-by: Natalia Tepluhina <tarya.se@gmail.com>

Co-authored-by: Natalia Tepluhina <tarya.se@gmail.com>

Author: jCodeLife

src/guide/typescript/composition-api.md

@@ -4,6 +4,8 @@
 
 ## Typing Component Props
 
+### Using `<script setup>`
+
 When using `<script setup>`, the `defineProps()` macro supports inferring the props types based on its argument:
 
 ```vue