Add C# example to Playing videos

[sighpher]

Add C# examples to Playing videos

[raulsntos]

I also noticed the code block in the Writing the Custom Shader section uses gd but it looks like we use glsl for shaders everywhere else. We may want to change it while we're updating this page.

[sighpher]

I also noticed the code block in the Writing the Custom Shader section uses gd but it looks like we use glsl for shaders everywhere else. We may want to change it while we're updating this page.

Great catch! ill update that too 😎

[raulsntos]

Looks good to me, thanks!

[AThousandShips]

Thanks!

[mhilbrunner]

Cherry-picked to 4.3 in #10038.