message: Add code block for multi-line comments in the docs.
diff: @@ -4,8 +4,8 @@ If a comment needs to contain newlines, you may do so by having an open quote, a
  begin parsing supplied commands that are terminated. Either double or single quotes may be used
  for this purpose, depending on which quoting rules that you need.
  +```ion
  echo "This is the first line
  this is the second line
  this is the third line"
  -
  -
  +```
  