patch 8.2.1314: Vim9: rule for comment after :function is confusing

Problem:    Vim9: rule for comment after :function is confusing.
Solution:   Allow double quoted comment after :function in vim9script.
            (closes #6556)
diff --git a/src/testdir/test_vim9_script.vim b/src/testdir/test_vim9_script.vim
index 427e912..b491fa2 100644
--- a/src/testdir/test_vim9_script.vim
+++ b/src/testdir/test_vim9_script.vim
@@ -2286,6 +2286,10 @@
       ])
   CheckScriptFailure([
       'vim9script',
+      'function " comment',
+      ], 'E129:')
+  CheckScriptFailure([
+      'vim9script',
       'function# comment',
       ], 'E129:')
   CheckScriptSuccess([
@@ -2333,11 +2337,11 @@
       'func Test() " comment',
       'endfunc',
       ])
-  CheckScriptFailure([
+  CheckScriptSuccess([
       'vim9script',
       'func Test() " comment',
       'endfunc',
-      ], 'E488:')
+      ])
 
   CheckScriptSuccess([
       'def Test() # comment',