Change visibility of PersistentEntitiesFactoryBean.

Also fix a javadoc parameter name mismatch along the way.

Closes: #651

Author: christophstrobl

src/main/java/org/springframework/data/r2dbc/config/PersistentEntitiesFactoryBean.java

@@ -26,14 +26,14 @@
  * @author Mark Paluch
  * @since 1.2
  */
-class PersistentEntitiesFactoryBean implements FactoryBean<PersistentEntities> {
+public class PersistentEntitiesFactoryBean implements FactoryBean<PersistentEntities> {
 
 	private final R2dbcMappingContext mappingContext;
 
 	/**
 	 * Creates a new {@link PersistentEntitiesFactoryBean} for the given {@link R2dbcMappingContext}.
 	 *
-	 * @param converter must not be {@literal null}.
+	 * @param mappingContext must not be {@literal null}.
 	 */
 	public PersistentEntitiesFactoryBean(R2dbcMappingContext mappingContext) {
 		this.mappingContext = mappingContext;