Bug 1766355 - part 5: Make HTMLEditor::MoveChildrenWithTransaction and HTMLEditor::MoveNodeOrChildrenWithTransaction stop touching Selection directly r=m_kato

Unfortunately, they call each other.  Therefore, this patch updates these 2
methods once.

Differential Revision: https://phabricator.services.mozilla.com/D146401

editor/libeditor/WSRunObject.cpp

@@ -460,10 +460,11 @@ EditActionResult WhiteSpaceVisibilityKeeper::
         moveNodeResult.isOk(),
         "HTMLEditor::MoveChildrenWithTransaction() failed, but ignored");
     if (moveNodeResult.isOk()) {
-      // When MoveNodeResult starts to store caret point, here does not do
-      // nothing.
+      // We don't need to update selection here because of dontChangeMySelection
+      // above.
       moveNodeResult.IgnoreCaretPointSuggestion();
       ret |= moveNodeResult;
+
 #ifdef DEBUG
       MOZ_ASSERT(!rightBlockHasContent.isErr());
       if (rightBlockHasContent.inspect()) {