Mention ScopedBlock in the UI reference (#11903)

docs/pages/contributing/documentation/reference.mdx

@@ -191,6 +191,36 @@ The `Figure` component can help with using images, figures, and diagrams:
 </Figure>
 ```
 
+## ScopedBlock
+
+Use the `ScopedBlock` component if you want to render some Markdown only for
+users of open source Teleport, Teleport Cloud, or Teleport Enterprise.
+
+`ScopedBlock` has a single property, `scope`, that works the same as it does for
+other components we use in the documentation. See our
+[explanation](./reference.mdx#scopes) of how to use the `scope` property.
+
+Use this instead of the `Tabs` component when:
+
+- You want to conceal details that aren't relevant to the reader's scope.
+- The components you use don't look presentable within a `TabItem`, e.g., you're
+  including a separate `Tabs` component for each scope.
+
+Any Markdown and MDX components can be included within a `ScopedBlock`.
+
+```jsx
+<ScopedBlock scope={["oss", "enterprise"]}>
+
+  Here are some options for installing the Teleport Auth and Proxy Services on
+  your own infrastructure.
+
+  <Tabs>
+  {/* TabItems that vary between scopes */}
+  </Tabs>
+
+</ScopedBlock>
+```
+
 ## Videos
 To embed a video in a docs page, use the `video` tag:
 ```html