patch 9.1.0015: i_CTRL-R- no longer works in replace mode

Problem:  i_CTRL-R- no longer works in replace mode
Solution: delete characters in replace mode before putting, add a test,
          add a bit warning into the documentation, that i_CTRL-R-P/O
          is not supported in Replace mode for now

fixes: #13792
closes: #13816

Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/src/testdir/test_normal.vim b/src/testdir/test_normal.vim
index 90bedf1..38ad810 100644
--- a/src/testdir/test_normal.vim
+++ b/src/testdir/test_normal.vim
@@ -4181,4 +4181,4 @@
   bw!
 endfunc
 
-" vim: shiftwidth=2 sts=2 expandtab
+" vim: shiftwidth=2 sts=2 expandtab nofoldenable