corrected the expression

Author: michalChrobot

.yamato/_triggers.yml

@@ -75,9 +75,10 @@ pull_request_trigger:
     - .yamato/desktop-standalone-tests.yml#desktop_standalone_test_testproject_win_il2cpp_6000.0
     - .yamato/cmb-service-standalone-tests.yml#cmb_service_standalone_test_testproject_ubuntu_il2cpp_trunk
   triggers:
-    cancel_old_ci: true
     expression: |-
-      pull_request.comment eq "ngo"
+      pull_request.comment eq "ngo" AND
+      NOT pull_request.changes.all match "**/Documentation~/**"
+    cancel_old_ci: true
 
 # Run all tests on trunk on nightly basis.
 # Same subset as pull_request_trigger with addition of mobile/desktop/console tests and webgl builds