Update README.md
Some clarification and markdown for boelle notes
Merge pull request #1230 from thinkyhead/readme_tweak

Clarification and markdown for boelle notes
Merge commit 'f05225a27165ae6635cbf1f2a0594acbfeac6f28' into Marlin_phoenix

* commit 'f05225a27165ae6635cbf1f2a0594acbfeac6f28':
  Update README.md
Merge commit 'f05225a27165ae6635cbf1f2a0594acbfeac6f28' into Marlin_phoenix_z_probe

* commit 'f05225a27165ae6635cbf1f2a0594acbfeac6f28':
  Update README.md
Merge commit 'a0c43f17141eea17bfc60e2ba20206ba7e31de4b' into Marlin_phoenix_z_probe

* commit 'a0c43f17141eea17bfc60e2ba20206ba7e31de4b':
Merge commit '7250ec4337aae5c5f0e371ac69867f3b4d6a150d' into Marlin_phoenix_z_probe

* commit '7250ec4337aae5c5f0e371ac69867f3b4d6a150d':
  Some clarification and markdown for boelle notes
Merge commit '529c937943f98d6c433962915135ab19adec5c1c' into Marlin_phoenix_z_probe

* commit '529c937943f98d6c433962915135ab19adec5c1c':