tests/test-debugindexdot.out

doc/style: use default font color specified by user

* it's bad to specify only foreground color:
  http://www.w3.org/QA/Tips/color
* some people prefer dark background
* `color: #111' is mostly the same as `color: black',
  which is the default of almost all popular browsers.

so it's preferable to delete `color: #111', rather than adding
`background-color: white'.

created new head
digraph G {
	-1 -> 0
	0 -> 1
	0 -> 2
	2 -> 3
	1 -> 3
}