Mentioned known issues with cucumber-json-formatter

Author: badeball

docs/json-report.md

@@ -61,3 +61,13 @@ Given("a step", function() {
   attach("Zm9vYmFy", "base64:text/plain");
 });
 ```
+
+## Known issues
+
+Some issues with `cucumber-json-formatter` are known and don't need to be reported again.
+
+- Inaccurate output of `match` on undefined step definition (https://github.com/cucumber/json-formatter/issues/2)
+
+- Inaccurate output of retried scenarios (https://github.com/cucumber/json-formatter/issues/4)
+
+- Inaccurate output of scenario outlined with parameterized name (https://github.com/cucumber/json-formatter/issues/25)