tdf#112202 writerfilter,sw: fix loss of headers

There are several problems here:

* CloseSectionGroup() is not only called for actual sections in the
document but also at the end of every special text like comment,
footnote, etc; only actual sections can set page styles. Writer
comments use editengine so cannot even contain sections.

* With continous section breaks, headers and footers are inherited from
the previous section unless defined by the current section;
SwXText::copyText() did not copy the content of the header on page 4
to page 5 correctly because it used an SwXTextCursor to create the
selection, which cannot select the table at the start of the header.

* For continuous section breaks, WW8 import filter has a heuristic to
find the first page break in the section and set the PageDescName
property on that node to apply the page style with the headers of the
new section; do something similar in writerfilter
SectionPropertyMap::CloseSectionGroup()

Change-Id: I3ebe3d299f83197cbf8f10de46c34de98677626c
Reviewed-on: https://gerrit.libreoffice.org/85213
Tested-by: Jenkins
Reviewed-by: Michael Stahl <michael.stahl@cib.de>

0 files changed, 0 insertions, 0 deletions