Update Libraries-and-Plugins.html (#24947)

> Threlte is a component library for Svelte to build and render three.js scenes declaratively and state-driven in Svelte apps.

docs/manual/en/introduction/Libraries-and-Plugins.html

@@ -101,6 +101,7 @@
 			<li>[link:https://aframe.io/ A-Frame]</li>
 			<li>[link:https://github.com/pmndrs/react-three-fiber react-three-fiber]</li>
 			<li>[link:https://github.com/ecsyjs/ecsy-three ECSY]</li>
+			<li>[link:https://threlte.xyz/ Threlte]</li>
 		</ul>
 
 	</body>