We'd like to use react-markdown in a project, but we'd like to extend it to support markdown-it plugins and a couple more decorators. We're targeting supporting centering text, highlighting, and underline. Do you have a guide on adding buttons and decorators or a couple pointers where to start? I noticed https://opuscapita.github.io/react-markdown//branches/master/index.html?currentComponentName=MarkdownInput which allows me to define extensions as buttons, and even a renderer. Is this all I need to do?