vim-patch:9.1.1121: Enter does not insert newline with "noselect"

Problem:  Enter does not insert newline with "noselect" when the pum is
          visible (lifepillar)
Solution: When Enter is pressed and no complete-item is selected,
          ins_compl_prep returns false, and the edit function continues
          processing Enter to insert a new line. (glepnir)

fixes: vim/vim#1653
closes: vim/vim#16653

07f0dbe3aa

Co-authored-by: glepnir <glephunter@gmail.com>

test/functional/legacy/edit_spec.lua

@@ -92,4 +92,28 @@ describe('edit', function()
                                                                   |
     ]])
   end)
+
+  -- oldtest: Test_edit_CAR()
+  it('insert a newline when pressing Enter, even if the pum is visible', function()
+    local screen = Screen.new(10, 6)
+    command('set cot=menu,menuone,noselect')
+    feed('Shello hero<CR>h<C-X><C-N>e')
+    screen:expect([[
+      hello hero  |
+      he^          |
+      {4:hello       }|
+      {4:hero        }|
+      {1:~           }|
+      {5:--}          |
+    ]])
+
+    feed('<CR>')
+    screen:expect([[
+      hello hero  |
+      he          |
+      ^            |
+      {1:~           }|*2
+      {5:-- INSERT --}|
+    ]])
+  end)
 end)