feat: add tests for all help commands

tests/unit/40_trace.bats

@@ -24,6 +24,20 @@ teardown() {
   assert_success
 }
 
+@test "(trace) trace:help" {
+  run /bin/bash -c "dokku trace"
+  echo "output: $output"
+  echo "status: $status"
+  assert_output_contains "Manage trace mode"
+  help_output="$output"
+
+  run /bin/bash -c "dokku trace:help"
+  echo "output: $output"
+  echo "status: $status"
+  assert_output_contains "Manage trace mode"
+  assert_output "$help_output"
+}
+
 @test "(trace) trace on" {
   run /bin/bash -c "dokku trace on"
   echo "output: $output"