no more basic theme. migrating to LeptonX Lite

docs/en/UI/AspNetCore/Basic-Theme.md

@@ -10,7 +10,7 @@ The Basic Theme has RTL (Right-to-Left language) support.
 
 ## Installation
 
-**This theme is already installed** when you create a new solution using the [startup templates](../../Startup-Templates/Index.md). If you need to manually install it, follow the steps below:
+If you need to manually this theme, follow the steps below:
 
 * Install the [Volo.Abp.AspNetCore.Mvc.UI.Theme.Basic](https://www.nuget.org/packages/Volo.Abp.AspNetCore.Mvc.UI.Theme.Basic) NuGet package to your web project.
 * Add `AbpAspNetCoreMvcUiBasicThemeModule` into the `[DependsOn(...)]` attribute for your [module class](../../Module-Development-Basics.md) in the web project.