credocument: update getTextFromXPointers wrapper to support selections
credocument: update getTextFromXPointers wrapper to support selections

With the latest koreader-base update, we can now create native
selections using getTextFromXPointers. In order to make the wrapper less
annoying to use, always enable segmented selection if selections are
enabled (to match getTextFromPositions).

Signed-off-by: Aleksa Sarai <b305c9b0212d6145eea67bbffd24e29cb79c759c@cyphar.com>

koreader/koreader,Frenzie/koreader,koreader/koreader,Frenzie/koreader,NiLuJe/koreader,poire-z/koreader,poire-z/koreader,NiLuJe/koreader