Dear All,

I'm sending you some updates to the ORG manual.
I'm sorry there's a lot of changes in this one patch.
If it's too much, I think I could break the changes into two commits:

First, move the 'Checkboxes' section under 'TODO Items' to '2 Document
Structure' -> '2.6 Plain Lists' -> '2.6.2 Checkboxes' because 'Checkbox'
can only exist in plain list items.
Second, all other updates -> about Checkboxes and TODO items cookie
statistics.

What do you think?

Patch in the attachment.
Thank you for the code review.
Now please help me find everything that can be improved in this patch.

Regards,
Sławomir Grochowski