patch 8.2.3521: options completion test fails

Problem:    Options completion test fails.
Solution:   Add 'thesaurusfunc' to the results.
diff --git a/src/testdir/test_options.vim b/src/testdir/test_options.vim
index e10ad54..3e9bbf4 100644
--- a/src/testdir/test_options.vim
+++ b/src/testdir/test_options.vim
@@ -256,7 +256,7 @@
 
   " Expand abbreviation of options.
   call feedkeys(":set ts\<C-A>\<C-B>\"\<CR>", 'tx')
-  call assert_equal('"set tabstop thesaurus ttyscroll', @:)
+  call assert_equal('"set tabstop thesaurus thesaurusfunc ttyscroll', @:)
 
   " Expand current value
   call feedkeys(":set fileencodings=\<C-A>\<C-B>\"\<CR>", 'tx')