This commit replaces the melos doc-build-live with melos doc-serve.
This also changes documentation for this while removing the mention of make commands in the documentation.
Fix several errors reported during documentation build.
Generally speaking,
```foo
would be interpreted as a code block with the language foo; while
```{foo}
would be interpreted as a Sphinx directive .. foo.
Additional mode "infobox" allows Flutter widgets to be inserted into the generated documentation site as wikipedia-style infoboxes floating on the right. This is useful for presenting content to the user up-front without sacrificing the flow of the exposition. For example, currently the Tap Events demo is "hidden" in the middle of a long page.
We believe that presenting the content in this way would make the user more excited to read about it.
