Document new PlayVideo flags as enum

[ericoporto]

Since 3.6.3, PlayVideo can take the flags as enum.

/// Plays a video file of any supported format.
import void PlayVideo(const string filename, VideoSkipStyle, VideoPlayStyle style);

The enum is as follow

enum VideoPlayStyle
{
  eVideoPlayDefault = 0,
  eVideoPlayStretchToScreen = 1,
  eVideoPlayNoAudio = 10,
  eVideoPlayAudioAndDontMuteGame = 20
};

Need to adjust both StandardEnums and Multimedia entries.

https://github.com/adventuregamestudio/ags-manual-source/blob/ce58d5dc7ef8f7a8e85da850db3d3fce3b418e55/Multimedia.md?plain=1#L142-L147

https://github.com/adventuregamestudio/ags-manual-source/blob/master/StandardEnums.md

[AlanDrake]

Entries added, check if it's clear enough