Fix max_complexity_reached: use actual run max, not 1000

When there are no failures, max_complexity_reached was set to
max_possible (1000) instead of the highest complexity actually
present in the run. Now uses sorted_complexities.max so a suite
with max complexity 500 shows '500 of 1000' not '1000 of 1000'.

Author: tobi

lib/liquid/spec/cli/runner.rb

@@ -498,7 +498,7 @@ def run_specs_frozen(config, options, run_id)
             max_complexity_reached = if first_failure_complexity
               sorted_complexities.select { |c| c < first_failure_complexity }.max || 0
             else
-              max_possible
+              sorted_complexities.max || 0
             end
 
             if json_mode