chore: fix spacing

Author: paoloricciuti

README.md

@@ -1,8 +1,8 @@
 <a href="https://svelte.dev">
 	<picture>
-      <source media="(prefers-color-scheme: dark)" srcset="assets/banner_dark.png">
-      <img src="assets/banner.png" alt="Svelte - web development for the rest of us" />
-  </picture>
+		<source media="(prefers-color-scheme: dark)" srcset="assets/banner_dark.png">
+		<img src="assets/banner.png" alt="Svelte - web development for the rest of us" />
+	</picture>
 </a>
 
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