Fix markup in updated kstars docbooks

improve markup
remove recently added ellipses (...) in <gui*> markup, has a meaning only in the GUI
use entites (&kstars; &ie;)
use preferred words (Internet)
partly already committed by yurchor with http://commits.kde.org/kstars/c9cfaf90e2f6ece1eed97627e90a235ba7a5dcb9
REVIEW:128407