patch 8.2.3633: Vim9: line number of lambda is off by one

Problem:    Vim9: line number of lambda is off by one.
Solution:   Add one to the line number. (closes #9083)

src/testdir/test_vim9_func.vim

@@ -1052,6 +1052,20 @@ def Test_call_lambda_args()
   CheckScriptFailure(['vim9script'] + lines, 'E118: Too many arguments for function: <lambda>', 2)
 enddef
 
+def Test_lambda_line_nr()
+  var lines =<< trim END
+      vim9script
+      # comment
+      # comment
+      var id = timer_start(1'000, (_) => 0)
+      var out = execute('verbose ' .. timer_info(id)[0].callback
+          ->string()
+          ->substitute("('\\|')", ' ', 'g'))
+      assert_match('Last set from .* line 4', out)
+  END
+  CheckScriptSuccess(lines)
+enddef
+
 def FilterWithCond(x: string, Cond: func(string): bool): bool
   return Cond(x)
 enddef