patch 9.2.0873: :redrawstatus does not update the ruler of the last window

patch 9.2.0873: :redrawstatus does not update the ruler of the last window

Problem:  When the last window has no status line the ruler takes its
          place in the last screen line, but ":redrawstatus" and
          re-setting 'rulerformat' or 'statusline' do not update it
          there.  An item such as a clock in 'rulerformat' can therefore
          not be refreshed from a timer (watael)
Solution: Also mark the ruler for redrawing when the last window has no
          status line and 'ruler' is set.  Update the documentation,
          tests and add a new test (Hirohito Higashi)

Reported: https://groups.google.com/g/vim_use/c/VKCL2bH8xlk
closes: #20865

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Signed-off-by: Hirohito Higashi <h.east.727@gmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>