doc: list styles update - a new list style for each paragraph

* I noticed a regression on my lists_support test files. The inheritance of text-properties
in textlayout was broken for a while on DOC files so I did not notice it that time.
The regression was introduced around the text:continue-list support.

* The point is that a new list style must be prepared for each paragraph becasue even a single
text-property might differ. This does not affect text:continue-list support.