Provide more detailed documentation how `transform` `matrix` works

[psnet]

Introduction

In official docs there is no any information about how matrix functionality works. Need to add more description because of matrix: number[] is not informative

Details

transform([
    {
        matrix: []      // what it does?
    }
])

[shergin]

I believe, the doc should state that the RN implementation should match iOS one (which is pretty much industry standard).