add highlighting for ON_SUCCESS

syntaxes/rmchAddOn.tmLanguage.json

@@ -161,7 +161,7 @@
 	  "keyword_control": {
 		"patterns": [
 		  {
-			"match": "(?x)\n\\b(skip|BE|DO|VARIANT|ELSIF|THEN|ELSE|EITHER|CASE|SELECT\n|ASSERT|WHERE|WHEN|OR|OF|IN|BODY|GOAL|DEPENDS_ON_RULE|DEPENDS_ON_COMPUTATION|ACTIVATION|REPLACES|ERROR_TYPES|CLASSIFICATION|RULEID|TAGS|BODY|EXPECT|ERROR_TYPE|COUNTEREXAMPLE|DEFINE|TYPE|DUMMY_VALUE|VALUE|PRECONDITION|POSTCONDITION)\\b",
+			"match": "(?x)\n\\b(skip|BE|DO|VARIANT|ELSIF|THEN|ELSE|EITHER|CASE|SELECT\n|ASSERT|WHERE|WHEN|OR|OF|IN|BODY|GOAL|DEPENDS_ON_RULE|DEPENDS_ON_COMPUTATION|ACTIVATION|REPLACES|ERROR_TYPES|CLASSIFICATION|RULEID|TAGS|BODY|EXPECT|ERROR_TYPE|ON_SUCCESS|COUNTEREXAMPLE|DEFINE|TYPE|DUMMY_VALUE|VALUE|PRECONDITION|POSTCONDITION)\\b",
 			"name": "keyword.control.rmchAddOn"
 		  }
 		]