docs: update links & improve custom slot knowledge base entry (#6752)

UI5/webcomponents#10386 (comment)

Author: Lukas742

docs/Welcome.mdx

@@ -103,10 +103,7 @@ UI5 Web Components and UI5 Web Components for React are both coming with the `sa
   children={
     <>
       UI5 Web Components for React uses the theme configuration of UI5 Web Components. Please also have a look at their{' '}
-      <Link href="https://sap.github.io/ui5-webcomponents/playground/?path=/docs/docs-advanced-configuration--docs#theme">
-        documentation
-      </Link>
-      .
+      <Link href="https://sap.github.io/ui5-webcomponents/docs/advanced/configuration/#theme">documentation</Link>.
     </>
   }
 />
@@ -182,7 +179,7 @@ export default function App() {
 
 ### Feature Registration
 
-`@ui5/webcomponents` offers a variety of [feature (side-effect) imports](https://sap.github.io/ui5-webcomponents/playground/?path=/docs/docs-getting-started-using-features) that are available with `@ui5/webcomponents-react` as well.
+`@ui5/webcomponents` offers a variety of [feature (side-effect) imports](https://sap.github.io/ui5-webcomponents/docs/advanced/using-features/) that are available with `@ui5/webcomponents-react` as well.
 To use them you have to make sure they are imported before any other imports!
 
 ### Support

docs/knowledge-base/CustomComponentsSlots.mdx

@@ -1,10 +1,16 @@
 import { Meta } from '@storybook/addon-docs';
 import { BarComponent, FaultyBarComponent } from '../knowledgeBaseExamples/slotExamples';
 import { Footer } from '@sb/components';
+import { MessageStrip } from '@ui5/webcomponents-react';
 
 <Meta title="Handling Slots" />
 
-# Adding custom components to slots
+# Adding custom React components to slots
+
+<MessageStrip
+  hideCloseButton
+  children="Using a custom React component still requires the expected web component(s) to be rendered."
+/>
 
 With our wrapper we provide an easy way to consume the `slots` of the UI5 Web Components by attaching them to a `prop`.
 In most cases you don't have to take anything into account, and the props can be used in a typical React way. However, there is an exception with custom components:

docs/knowledge-base/Internationalization.mdx

@@ -29,7 +29,7 @@ That's it! You can now test whether the translations work correctly by adding e.
 
 ## How to add custom translations
 
-_Please also read the [general configuration](https://sap.github.io/ui5-webcomponents/playground/?path=/docs/docs-advanced-configuration) and [i18n documentation](https://sap.github.io/ui5-webcomponents/playground/?path=/docs/docs-advanced-using-i18n-for-apps) of UI5 Web Components._
+_Please also read the [general configuration](https://sap.github.io/ui5-webcomponents/docs/advanced/configuration/) and [i18n documentation](https://sap.github.io/ui5-webcomponents/docs/advanced/using-i18n-for-apps/) of UI5 Web Components._
 
 <MessageStrip
   design={MessageStripDesign.Information}
@@ -39,7 +39,7 @@ _Please also read the [general configuration](https://sap.github.io/ui5-webcompo
       When using custom translations, you have to enable the <code>fetchDefaultLanguage</code> option for UI5 Web
       Components. If it is not set, your default language translations (english) will be missing. Learn more about it{' '}
       <a
-        href="https://sap.github.io/ui5-webcomponents/playground/?path=/docs/docs-advanced-configuration--docs#fetchdefaultlanguage"
+        href="https://sap.github.io/ui5-webcomponents/docs/advanced/configuration/#fetchDefaultLanguage"
         target="_blank"
       >
         here

packages/main/src/components/MessageView/MessageView.stories.tsx

@@ -48,7 +48,7 @@ const meta = {
       <MessageItem
         key={3}
         titleText={'Warning Message Type'}
-        subtitleText={'Warnign without details'}
+        subtitleText={'Warning without details'}
         type={ValueState.Critical}
         counter={3}
       />,