Fix cursor position after redo

Fix cursor position after redo

When document settings are modified, a command
  inset-forall Branch inset-toggle asign
is run to open as needed all branches. At the end of the said loop,
the cursor is reset to where it was. However, the cur_after undo
element member is not set because it already had a value.

To make this work as expected, it is necessary in LFUN_INSET_FORALL to
reset the cursor before ending the undo group and to insert a dummy
recordUndo call.

Fixes bug #10097.