Explain status codes

Author: limbonaut

.github/workflows/unit_tests.yml

@@ -54,7 +54,7 @@ jobs:
           SENTRY_TEST: 1
           SENTRY_TEST_INCLUDE: "res://test/suites/"
         run: |
-          # Exit status codes: 0 - success, 100 - ends with test failures, 101 - ends with test warnings, 204 - no tests found.
+          # Exit status codes: 0 - success, 100 - failures, 101 - warnings, 200 - didn't run, 204 - tests not found.
           ${GODOT} --headless --debug --path project/
 
       - name: Run isolated tests