fdo#60732: SwTxtNode: limit to less than STRING_LEN chars

It's not a good idea to have STRING_LEN characters in a SwTxtNode
because then there is no valid SwPosition at the end of the paragraph.
Also it turns out that LO 3.6 and 4.0 do rather stupid things with a
full SwTxtNode.  So enforce a limit, at first in the usual places that
are used during file import, SwTxtNode::InsertText() and
SwCntntNode::CanJoinPrev()/CanJoinNext().

(cherry picked from commit 549c0f785d4b6d4bc1b39b22827d77d66f48430a)

Conflicts:
	sw/source/core/docnode/node.cxx

Change-Id: Icb0f44acd20aa81635d42b84d4ae0f9b693a661c
Reviewed-on: https://gerrit.libreoffice.org/2178
Reviewed-by: Miklos Vajna <vmiklos@suse.cz>
Tested-by: Miklos Vajna <vmiklos@suse.cz>

0 files changed, 0 insertions, 0 deletions