patch 8.2.3783: confusing error for using a variable as a function

Problem:    Confusing error for using a variable as a function.
Solution:   If a function is not found but there is a variable, give a more
            useful error. (issue #9310)

src/testdir/test_vim9_script.vim

@@ -1922,6 +1922,15 @@ def Test_script_var_shadows_command()
   CheckDefAndScriptFailure(lines, 'E1207:', 2)
 enddef
 
+def Test_vim9script_call_wrong_type()
+  var lines =<< trim END
+      vim9script
+      var Time = 'localtime'
+      Time()
+  END
+  CheckScriptFailure(lines, 'E1085:')
+enddef
+
 def s:RetSome(): string
   return 'some'
 enddef