minor fixes in examples

Author: StuartMosquera

samples/snippets/fsharp/compiler-messages/fs0067.fsx

@@ -5,7 +5,7 @@ type Dog() =
 let dog = Dog()
 
 if dog :? Dog then
-    printfn "It always be a dog"
+    printfn "It's of type: %s" dog.Name
 
 (* Redundant Downcast *)
 type Cat(name: string) =
@@ -15,4 +15,4 @@ let cat = Cat("Kitten")
 
 let sameCat = cat :?> Cat
 
-printfn "It's still a %s" sameCat.Name
+printfn "It still a %s" sameCat.Name