patch 8.2.1593: tests do not check the error number properly

Problem:    Tests do not check the error number properly.0
Solution:   Add a colon after the error number. (closes #6869)
diff --git a/src/testdir/test_vim9_func.vim b/src/testdir/test_vim9_func.vim
index 3e21730..828dbba 100644
--- a/src/testdir/test_vim9_func.vim
+++ b/src/testdir/test_vim9_func.vim
@@ -523,7 +523,7 @@
 
 def Test_error_in_nested_function()
   # Error in called function requires unwinding the call stack.
-  assert_fails('call FuncWithForwardCall()', 'E1096')
+  assert_fails('call FuncWithForwardCall()', 'E1096:')
 enddef
 
 def Test_return_type_wrong()
@@ -735,8 +735,8 @@
     CallGoneSoon()
   END
   writefile(lines, 'XToDelFunc')
-  assert_fails('so XToDelFunc', 'E933')
-  assert_fails('so XToDelFunc', 'E933')
+  assert_fails('so XToDelFunc', 'E933:')
+  assert_fails('so XToDelFunc', 'E933:')
 
   delete('XToDelFunc')
 enddef