Add Combine & NavigationStack content to the iOS roadmap (#6052)

Add content to Navigated stacks and combine

src/data/roadmaps/ios/content/combine@UzpdLLPs226N00c6weWRv.md

@@ -1 +1,9 @@
-# Combine
+# Combine
+Combine is Apple's built-in framework for reactive programming, using the same publisher-subscriber pattern as most modern approaches to this issue.
+Combine introduces the concept of a `Cancellable` (i.e. a subscription) and many different operators to use on these Cancellables.
+When writing Combine code, developers will notice complex generic types. For this reason, type-erasure can be done through `AnyCancellable`.
+
+Visit the following resources to learn more:
+
+- [@official@Combine](https://developer.apple.com/documentation/combine)
+- [@video@Understanding Combine](https://youtu.be/rz0yx0Qz2jE)

src/data/roadmaps/ios/content/navigation-stacks@TLm70PlTI0K3Odn1iYxWX.md

@@ -1 +1,11 @@
-# Navigation Stacks
+# Navigation Stacks
+
+iOS 16 introduced a new concept of navigating through SiwftUI apps: NavigationStack.
+NavigationStack is data-driven, meaning that you specify navigationDestinations for each data type (models) that your app supports.
+These destinations are defined once for each NavigationStack and are valid throughout the app.
+Navigation itself is handled through the NavigationLink View, which allows setting a label and a value (your model).
+
+Visit the following resources to learn more:
+
+- [@official@NavigationStack](https://developer.apple.com/documentation/swiftui/navigationstack)
+- [@video@NavigationStack](https://www.youtube.com/watch?v=DMsALlhObNk)