fix: pixi.md docs

[furic]

Remove the extra brackets, which is an invalid JSON format.

For example, it should be:

pixiPipes({
	texturePacker: { texturePacker: { nameStyle: 'short' }},
}),

Instead of :

pixiPipes({
	texturePacker: {{ texturePacker: { nameStyle: 'short' }}},
}),

P.S. I found having two texturePacker keys confusing and couldn't get it to work with just one on the first try.