Report fixes for the doc

[Antoni Bella Pérez]

  Hi list,

  I'm working on updating the latest changes (Catalan translation) and found 
some mistakes, reported below.

Kate:
  I found three screenshots missing:

  backtrace-setting.png
  filtertext.png
  projects-search.png

Dolphin:
  I found three occurrences of an entity empty:

  &kappname; -> &dolphin;

KInfocenter:
  This button has changed:

  Now press <guibutton>clear</guibutton>.
  Now press <guibutton>Clear Results</guibutton>.

  Regards
  Toni