Added pattern matching info in Remote Control Car introduction

exercises/concept/remote-control-car/.docs/introduction.md

@@ -35,6 +35,16 @@ Since structs are built on maps, we can use most map functions to get and manipu
   # => %Plane{engine: nil, wings: 4}
   ```
 
+Structs can also be used in pattern matching for ensuring that the matching value is a struct of the same type as the matched value.
+```elixir
+defmodule Helicopter do
+  defstruct [:engine, rotors: 1]
+end
+
+%Plane{} = %Helicopter{}
+# => (MatchError) no match of right hand side value: %Helicopter{engine: nil, rotors: 1}
+```
+
 ### Enforcing field value initialization
 
 We can use the `@enforce_keys` module attribute with a list of the field keys to ensure that the values are initialized when the struct is created. If a key is not listed, its value will be `nil` as seen in the above example. If an enforced key is not initialized, an error is raised.