docs(aria): add information about axe-core

Author: AdrianRomanski

src/aria/disclosure/disclosure.spec.ts

@@ -56,6 +56,10 @@ describe('Disclosure Directives', () => {
     component = fixture.componentInstance;
   }
 
+  /**
+   * Accessibility is validated after each test using axe-core.
+   * @see https://github.com/dequelabs/axe-core
+   */
   afterEach(async () => {
     await runAccessibilityChecks(fixture.nativeElement);
   });