Pass full node to renderMark and/or allow overriding renderText

[janus-reith]

I apply custom styles to my marks, e.g. color, similar to how it's done in the Lexical playground.

Therefore I need to parse style:

const renderText = React.useCallback(
    (node: TextNode): React.ReactNode | null => {
      if (!renderMark) {
        throw new Error("'renderMark' prop not provided.");
      }

      if (!node.format) {
        return renderMark({
          text: node.text,
          style: node.style,
        });
      }

      return renderMark({
        text: node.text,
        bold: (node.format & IS_BOLD) > 0,
        [...]
        style: node.style,
      });
    },
    [renderMark]
  );

And use it like this:

  export const defaultRenderMark: RenderMark = (mark) => {
  const style: CSSProperties = { ...parseStyleString(mark.style) };

  [...]

  if (Object.keys(style).length === 0) {
    return <>{mark.text}</>;
  }

  return <span style={style}>{mark.text}</span>;
};

I had to fork the component in order to pass node.style to renderMark.

Some ideas:

1. A. Allow passing a custom function for renderText, similar to renderMark.
   B. Pass the full node to renderMark. In addition, consider removing renderText altogether and just calling a function that matches IS_BOLD etc. from within renderMark. That one could also be exported, so custom renderMark implementations could reuse it.
2. Consider making parsing of styles and maybe other relevant node attributes like class part of the included renderMark function.