Add extra dict possible for send to Chromecast (#16268)

Co-authored-by: Franck Nijhof <frenck@frenck.nl>

source/_integrations/media_player.markdown

@@ -48,6 +48,81 @@ Available services: `turn_on`, `turn_off`, `toggle`, `volume_up`, `volume_down`,
 | `entity_id`            |      yes | Target a specific media player. To target all media players, use `all`.                                                                                                                       |
 | `media_content_id`     |       no | A media identifier. The format of this is integration dependent. For example, you can provide URLs to Sonos and Cast but only a playlist ID to iTunes.                   |
 | `media_content_type`   |       no | A media type. Must be one of `music`, `tvshow`, `video`, `episode`, `channel` or `playlist`. For example, to play music you would set `media_content_type` to `music`. |
+| `extra`                |      yes | Extra dictionary data to send, e.g., title, thumbnail. Possible values can be found below.
+
+##### Extra dictionary data
+
+{% configuration %}
+title:
+  type: string
+  description: Title of the media.
+  required: false
+thumb:
+  type: string
+  description: Thumbnail image URL.
+  required: false
+current_time:
+  type: float
+  description: Seconds since the beginning of the content. If the content is live content, and the position is not specified, the stream will start at the live position.
+  required: false
+autoplay:
+  type: boolean
+  description: Whether the media will automatically play.
+  default: true
+  required: false
+stream_type:
+  type: string
+  description: "Describes the type of media artifact as one of the following: `NONE`, `BUFFERED`, `LIVE`."
+  required: false
+subtitles:
+  type: string
+  description: URL of subtitle file to be shown on chromecast.
+  required: false
+subtitles_lang:
+  type: string
+  description: Language for subtitles.
+  required: false
+subtitles_mime:
+  type: string
+  description: Mimetype of subtitles.
+  required: false
+subtitle_id:
+  type: integer
+  description: ID of subtitle to be loaded.
+  required: false
+enqueue:
+  type: boolean
+  description: If True, enqueue the media instead of play it.
+  default: false
+  required: false
+media_info:
+  type: map
+  description: Additional MediaInformation attributes not explicitly listed.
+  required: false
+metadata:
+  type: map
+  description: "Media metadata object, one of the following: `GenericMediaMetadata`, `MovieMediaMetadata`, `TvShowMediaMetadata`, `MusicTrackMediaMetadata`, `PhotoMediaMetadata`."
+  required: false
+{% endconfiguration %}
+
+Documentation:
+
+- [Google Dev Documentaion MediaData](https://developers.google.com/cast/docs/reference/messages#MediaData)
+- [Google Dev Documentaion MediaInformation](https://developers.google.com/cast/docs/reference/web_receiver/cast.framework.messages.MediaInformation)
+
+
+Example of calling media_player service with title and image set:
+
+```yaml
+entity_id: media_player.chromecast
+service: media_player.play_media
+data:
+  media_content_type: music
+  media_content_id: 'https://fake-home-assistant.io.stream/aac'
+  extra:
+    thumb: 'https://brands.home-assistant.io/_/homeassistant/logo.png'
+    title: HomeAssitantRadio
+```
 
 #### Service `media_player.select_source`