docs: add a small sumtype match example in the Match section too

doc/docs.md

@@ -1947,6 +1947,23 @@ println(typ)
 // 'lowercase'
 ```
 
+A match statement also can match the variant types of a `sumtype`. Note that
+in that case, the match is exhaustive, since all variant types are mentioned 
+explicitly, so there is no need for an `else{}` branch.
+
+```v nofmt
+struct Dog {}
+struct Cat {}
+struct Veasel {}
+type Animal = Dog | Cat | Veasel
+a := Animal(Veasel{})
+match a {
+	Dog { println('Bay') }
+	Cat { println('Meow') }
+	Veasel { println('Vrrrrr-eeee') } // see: https://www.youtube.com/watch?v=qTJEDyj2N0Q
+}
+```
+
 You can also use ranges as `match` patterns. If the value falls within the range
 of a branch, that branch will be executed.