patch 9.0.0081: command line completion of user command may have duplicates

Problem:    Command line completion of user command may have duplicates.
            (Dani Dickstein)
Solution:   Skip global user command if an identical buffer-local one is
            defined. (closes #10797)
diff --git a/src/testdir/test_cmdline.vim b/src/testdir/test_cmdline.vim
index a69774e..1994a8c 100644
--- a/src/testdir/test_cmdline.vim
+++ b/src/testdir/test_cmdline.vim
@@ -842,6 +842,16 @@
   delcommand Foo
 endfunc
 
+func Test_complete_user_cmd()
+  command FooBar echo 'global'
+  command -buffer FooBar echo 'local'
+  call feedkeys(":Foo\<C-A>\<Home>\"\<CR>", 'tx')
+  call assert_equal('"FooBar', @:)
+
+  delcommand -buffer FooBar
+  delcommand FooBar
+endfunc
+
 func s:ScriptLocalFunction()
   echo 'yes'
 endfunc