tests: Add comment that explain inqueue calculation

Signed-off-by: Kostiantyn Kostiuk <kkostiuk@redhat.com>

Author: kostyanf14

lib/engines/hcktest/tests.rb

@@ -329,6 +329,8 @@ def tests_stats
       cnt_failed = tests_stats_status_count(Models::HLK::TestResultStatus::Failed)
       total = @tests.count
 
+      # 'inqueue' means tests that are in AutoHCK queue not in HCK queue
+      # as we run tests one by one, we don't have tests in HCK queue
       { 'current' => current_test, 'passed' => cnt_passed,
         'failed' => cnt_failed, 'inqueue' => total - cnt_passed - cnt_failed,
         'skipped' => @playlist.rejected_test.count,