docs(angular): add case content (#6843)

src/data/roadmaps/angular/content/case@cHC2MH50CbUSMRZV4QGJI.md

@@ -1 +1,8 @@
-# @case
+# @case
+
+If no `@case` matches the `@switch` condition and there is no `@default` block, nothing is shown.  Otherwise, the content inside the `@case` that matches the condition will be displayed.
+
+Visit the following resources to learn more:
+
+- [@official@Angular Official Docs - @switch](https://angular.dev/guide/templates/control-flow#switch-block---selection)
+- [@article@Angular @switch: Complete Guide](https://blog.angular-university.io/angular-switch/)