fix renamer not respecting ACTION

src/main/java/de/tlc4b/analysis/Renamer.java

@@ -39,6 +39,7 @@ public class Renamer extends DepthFirstAdapter {
 	private final HashSet<String> globalNames;
 	private final static Set<String> KEYWORDS = new HashSet<>();
 	static {
+		KEYWORDS.add("ACTION");
 		KEYWORDS.add("ASSUME");
 		KEYWORDS.add("ASSUMPTION");
 		KEYWORDS.add("AXIOM");

src/test/java/de/tlc4b/tlc/integration/FixedBugs.java

@@ -6,7 +6,6 @@ import static org.junit.Assert.assertEquals;
 
 import org.junit.Test;
 
-
 public class FixedBugs {
 
 	@Test
@@ -20,4 +19,14 @@ public class FixedBugs {
 				+ "END";
 		assertEquals(Deadlock, testString(machine));
 	}
+
+	@Test
+	public void testActionIdentifier() throws Exception {
+		String machine =
+				"MACHINE Test\n"
+				+ "CONSTANTS ACTION\n"
+				+ "PROPERTIES ACTION={1, 2, 3} \n"
+				+ "END";
+		assertEquals(NoError, testString(machine));
+	}
 }