sw: fix AppendRedline() creating empty redlines for Outside
This happens on tdf#133967 bugdoc with the Delete/Delete case first, in
line 1445 - the start positions are equal, so the new redline is empty
=> DocumentRedlineManager.cxx:92: redline table corrupted: empty redline
Similar bugs exist for Delete/Insert case in line 1725 and Format/? case
in line 1892, the latter even checks a nonsensical condition
*pEnd != *pRStt that is always true for Outside case.
It's like that since inital CVS import.
Change-Id: I7ade25380a5a43b14e87db37da8fc84267e89dd2
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/99389
Tested-by: Jenkins
Reviewed-by: Michael Stahl <michael.stahl@cib.de>
(cherry picked from commit
632cc0507353c8a85e7438d6ef082bafb2a2137a)
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/99406
Reviewed-by: Thorsten Behrens <Thorsten.Behrens@CIB.de>