docs(angular): add structural directive content (#6524)

src/data/roadmaps/angular/content/structural-directives@xk3v8p6vf8ntGj5c-IU4U.md

@@ -1 +1,15 @@
-# Structural Directives
+# Structural Directives
+
+Structural directives are directives applied to an `<ng-template>` element that conditionally or repeatedly renders the content of that `<ng-template>`. If you just wrap elements in an `<ng-template>` without applying a structural directive, those elements will not be rendered.
+
+In Angular, there are three standard structural directives:
+
+- `*ngIf` – conditionally includes a template depending on the value of an expression returned by a Boolean.
+- `*ngFor` – makes it simple to iterate over an array.
+- `*ngSwitch` – renders each matching view.
+
+Visit the following resources to learn more:
+
+- [@official@Angular Official Docs - Structural Directives](https://angular.dev/guide/directives/structural-directives)
+- [@article@Structural Directives in Angular](https://medium.com/@eugeniyoz/structural-directives-in-angular-61fe522f3427)
+- [@article@Angular Structural Directive Patterns: What they are and how to use them](https://www.freecodecamp.org/news/angular-structural-directive-patterns-what-they-are-and-how-to-use-them/)