Support alternative NOT EQUALS operators in HQL.

Hibernate also supports "!=" and "^=" as NOT EQUALS operators.

See #2970
Original Pull Request #2972

spring-data-jpa/src/main/antlr4/org/springframework/data/jpa/repository/query/Hql.g4

@@ -533,8 +533,9 @@ expressionOrPredicate
     ;
 
 // https://docs.jboss.org/hibernate/orm/6.1/userguide/html_single/Hibernate_User_Guide.html#hql-relational-comparisons
+// NOTE: The TIP shows that "!=" is also supported. Hibernate's source code shows that "^=" is another NOT_EQUALS option as well.
 relationalExpression
-    : expression op=('=' | '>' | '>=' | '<' | '<=' | '<>' ) expression
+    : expression op=('=' | '>' | '>=' | '<' | '<=' | '<>' | '!=' | '^=' ) expression
     ;
 
 // https://docs.jboss.org/hibernate/orm/6.1/userguide/html_single/Hibernate_User_Guide.html#hql-between-predicate

spring-data-jpa/src/test/java/org/springframework/data/jpa/repository/query/HqlQueryRendererTests.java

@@ -564,6 +564,22 @@ class HqlQueryRendererTests {
 				""");
 	}
 
+	@Test // GH-2970
+	void alternateNotEqualsShouldAlsoWork() {
+
+		assertQuery("""
+				SELECT TYPE(e)
+				FROM Employee e
+				WHERE TYPE(e) != Exempt
+				""");
+
+		assertQuery("""
+				SELECT TYPE(e)
+				FROM Employee e
+				WHERE TYPE(e) ^= Exempt
+				""");
+	}
+
 	@Test
 	void theRest5() {