text: Title: Missing Array length
  Body: Hey,
  
  I worked in C# with this API and it was verry cool. But i missed something.
  
  It would be realy nice to have a field, wich shows the length of the following Array. 
  
  For example like this:
  
  ```
  "types_length": 2,
   "types": [
      {
        "slot": 1,
        "type": {
          "name": "grass",
          "url": "https://pokeapi.co/api/v2/type/12/"
        }
      },
      {
        "slot": 2,
        "type": {
          "name": "poison",
          "url": "https://pokeapi.co/api/v2/type/4/"
        }
      }
    ]
  ```