vim-patch:9.1.0075: insert completion not correct when adding new leader (#27332)

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

closes: vim/vim#13957

cbb46b4398

src/nvim/insexpand.c

@@ -1294,6 +1294,11 @@ void ins_compl_show_pum(void)
   pum_display(compl_match_array, compl_match_arraysize, cur, array_changed, 0);
   curwin->w_cursor.col = col;
 
+  // After adding leader, set the current match to shown match.
+  if (compl_started && compl_curr_match != compl_shown_match) {
+    compl_curr_match = compl_shown_match;
+  }
+
   if (has_event(EVENT_COMPLETECHANGED)) {
     trigger_complete_changed_event(cur);
   }

test/old/testdir/test_popup.vim

@@ -1162,9 +1162,21 @@ func Test_CompleteChanged()
   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