Docs: Move guides to manual. (#30736)

Author: Mugen87

docs/index.html

@@ -38,11 +38,9 @@ <h1><a href="https://threejs.org">three.js</a></h1>
 						<option value="ar">ar</option>
 						<option value="ko">한국어</option>
 						<option value="zh">中文</option>
-						<option value="ja">日本語</option>
 						<option value="it">it</option>
 						<option value="pt-br">pt-br</option>
 						<option value="fr">fr</option>
-						<option value="ru">ru</option>
 					</select>
 				</div>
 				<div id="content"></div>
@@ -93,7 +91,7 @@ <h1><a href="https://threejs.org">three.js</a></h1>
 
 			if ( /^(api|manual|examples)/.test( hash ) ) {
 
-				const hashLanguage = /^(api|manual|examples)\/(en|ar|ko|zh|ja|it|pt-br|fr|ru)\//.exec( hash );
+				const hashLanguage = /^(api|manual|examples)\/(en|ar|ko|zh|it|pt-br|fr)\//.exec( hash );
 
 				if ( hashLanguage === null ) {