docs(angular): add else content (#6716)

src/data/roadmaps/angular/content/else@ORdPDad4HWJAfcZuS-7yM.md

@@ -1 +1,8 @@
-# @else
+# @else
+
+While the `@if` block can be helpful in many situations, it's common to also show fallback UI when the condition is not met. When you need a fallback, similar to JavaScript's else clause, add an `@else` block to accomplish the same effect.
+
+Visit the following resources to learn more:
+
+- [@official@Angular Official Docs - @else block](https://angular.dev/essentials/conditionals-and-loops#else-block)
+- [@article@Angular If Else Control Flow Blocks Explained](https://ultimatecourses.com/blog/angular-if-else-control-flow-blocks-explained)