message: Add a Web defaults mode doc
  Closes
diff: @@ -191,3 +191,13 @@ Supported components:
  * Text (as a recipient)
  > Warning! Inheritance is not compatible with React Native.
  +
  +#### Web defaults
  +
  +Available under the flag `process.env.REACT_FIGMA_WEB_DEFAULTS_ENABLED`.
  +
  +On the Web defaults mode, react-figma will try to simulate Web default behavior:
  +
  +* A text with display: block should get full width (`width: 100%`)
  +* A container with display: flex should get `flexDirection: row`
  +* `alignItems: stretch` for containers by default
  