Update README.md

[MichaelCurrin]

• Fix typos
• Use sh or Dockerfile for codeblocks highlighting. Use console when there is output as it colors it different from $ lines.
• Remove words - it was self-evident that a command would do the 3 things listed in the comment so no need to say "all in one command". There is no step after so it is implied that it is all.
• Indent content in bullet points

[wsargent]

Thanks!