patch 9.1.0075: insert completion not correct when adding new leader

Problem:  insert completion not correct when adding new leader
Solution: Reset compl_curr_match to compl_shown_match
          (glepnir)

closes: #13957

Co-authored-by: glepnir <glephunter@gmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/src/testdir/test_popup.vim b/src/testdir/test_popup.vim
index a0a1f74..879d1fa 100644
--- a/src/testdir/test_popup.vim
+++ b/src/testdir/test_popup.vim
@@ -1159,9 +1159,21 @@
   call feedkeys("a\<C-N>\<C-N>\<C-N>\<C-N>\<C-P>", 'tx')
   call assert_equal('foobar', g:word)
 
+  func Omni_test(findstart, base)
+    if a:findstart
+      return col(".")
+    endif
+    return [#{word: "one"}, #{word: "two"}, #{word: "five"}]
+  endfunc
+  set omnifunc=Omni_test
+  set completeopt=menu,menuone
+  call feedkeys("i\<C-X>\<C-O>\<BS>\<BS>\<BS>f", 'tx')
+  call assert_equal('five', g:word)
+
   autocmd! AAAAA_Group
   set complete& completeopt&
   delfunc! OnPumChange
+  delfunc! Omni_test
   bw!
 endfunc