HSEARCH-4156 Don't try to infer mappedBy information from ManyToOne

ManyToOne never has any mappedBy information, it's always on the other
side. Worse: it sometimes holds a reference to a synthetic property
instead of the mappedBy, and trying to resolve that property leads to a
bootstrap failure since it doesn't exist.

Signed-off-by: Yoann Rodière <yoann@hibernate.org>

mapper/orm/src/main/java/org/hibernate/search/mapper/orm/mapping/impl/HibernateOrmMetatadaContributor.java

@@ -17,6 +17,7 @@
 import org.hibernate.mapping.Column;
 import org.hibernate.mapping.Component;
 import org.hibernate.mapping.OneToMany;
+import org.hibernate.mapping.OneToOne;
 import org.hibernate.mapping.PersistentClass;
 import org.hibernate.mapping.Property;
 import org.hibernate.mapping.Selectable;
@@ -139,10 +140,12 @@ private void collectPropertyMetadataContributors(PropertyDelegatesCollector coll
 				);
 			}
 		}
-		else if ( value instanceof ToOne ) {
-			ToOne toOneValue = (ToOne) value;
+		else if ( value instanceof OneToOne ) {
+			// ManyToOne never carries any useful inverse side information:
+			// either it refers to nothing or to a synthetic property that we're not interested in.
+			// OneToOne, on the other hand, uses ReferencedPropertyName to store the "mappedBy" information.
+			OneToOne toOneValue = (OneToOne) value;
 			String referencedEntityName = toOneValue.getReferencedEntityName();
-			// For *ToOne, the "mappedBy" information is apparently stored in the ReferencedPropertyName
 			String mappedByPath = toOneValue.getReferencedPropertyName();
 			if ( mappedByPath != null && !mappedByPath.isEmpty() ) {
 				collector.collect(