Docs: Clean up.

docs/manual/en/introduction/How-to-update-things.html

@@ -209,7 +209,7 @@ geometry.tangentsNeedUpdate = true;
 			<p>If the number is large (e.g. each face could be potentially different), consider a different solution, such as using attributes / textures to drive different per-face look.</p>
 
 			<h3>Examples:</h3>
-			[example:webgl_materials_cars WebGL / materials / cars]<br />
+			[example:webgl_materials_car WebGL / materials / car]<br />
 			[example:webgl_postprocessing_dof WebGL / webgl_postprocessing / dof]
 		</div>
 

docs/manual/zh/introduction/How-to-update-things.html

@@ -194,7 +194,7 @@ geometry.tangentsNeedUpdate = true;
 			<p>如果数量很大（例如，每个面可能有所不同），请考虑不同的解决方案，例如使用属性/纹理来驱动不同的每个面部外观。</p>
 
 			<h3>例子：</h3>
-			[example:webgl_materials_cars WebGL / materials / cars]<br />
+			[example:webgl_materials_car WebGL / materials / car]<br />
 			[example:webgl_postprocessing_dof WebGL / webgl_postprocessing / dof]
 		</div>