sw: invalidate paragraph signature on edit

Change-Id: I7267b1492f2eff043058a9322286f742338a2335
Reviewed-on: https://gerrit.libreoffice.org/41593
Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Ashod Nakashian <ashnakash@gmail.com>
diff --git a/sw/source/core/txtnode/ndtxt.cxx b/sw/source/core/txtnode/ndtxt.cxx
index 8391a65..8031dd2 100644
--- a/sw/source/core/txtnode/ndtxt.cxx
+++ b/sw/source/core/txtnode/ndtxt.cxx
@@ -1211,6 +1211,12 @@ void SwTextNode::Update(
    if (pSortedObjs)
        pSortedObjs->UpdateAll();

    // Update the paragraph signatures.
    if (SwEditShell* pEditShell = GetDoc()->GetEditShell())
    {
        pEditShell->ValidateParagraphSignatures(false);
    }

    // Inform LOK clients about change in position of redlines (if any)
    if (comphelper::LibreOfficeKit::isActive())
    {