improving docs

[tomByrer]

Here I'll document how I think the docs could be better.

[tomByrer]

Fundamentals

Section ordering: should be listed in top-down as the render tree happens:

1. index.jsx
2. <Composition> in video.jsx
3. simple component (I would call it a 'slide' or 'frame' used by first <Composition>
4. complicated component using Video properties

[tomByrer]

Reuse components

Might be better immediately after Fundamentals; reinforces that <Sequence> are lower in the 'tree' inside <Composition>, feels more like React.

Animations / transitions are an embellishment of existing components, part of the preview-edit loop.