FakeVim: Break edit block by editing cursor line

Break edit block at current line so that other line is not marked as
changed.

Change-Id: Iea1c3615899fdd3558861e7f3a319f796c5f247b
Reviewed-by: hjk <hjk121@nokiamail.com>

src/plugins/fakevim/fakevimhandler.cpp

@@ -7035,7 +7035,8 @@ void FakeVimHandler::Private::joinPreviousEditBlock()
     UNDO_DEBUG("JOIN");
     if (m_breakEditBlock) {
         beginEditBlock();
-        QTextCursor tc(document());
+        QTextCursor tc(cursor());
+        tc.setPosition(tc.position());
         tc.beginEditBlock();
         tc.insertText(_("X"));
         tc.deletePreviousChar();