Asciidoc note with quoted-code sample

Tested at https://asciidoclive.com/edit/scratch/1

with markup below:

[NOTE]
====
This is some text to note and source below:

[source,python]
-----------------
#!/usr/bin/env python
import antigravity
try:
  antigravity.fly()
except FlytimeError as e:
  # um...not sure what to do now.
  pass
-----------------

====