The comment on first line of the code example is 82 characters long
and is cut on the 80-th character when viewed online. The second line
contains only two letters "on" without # in front.
The comment is displayed on two lines anyway, it is better if it is split to
two lines of less than 80 characters.
Updates the docs and clarifies the usage of `do_token` variable.
I was experiencing an issue mentioned here https://github.com/hashicorp/terraform/issues/124 and so adding more docs should be helpful.