Polish "Restore customization of PropertyResolver"

See gh-26761

Author: snicoll

spring-context/src/main/java/org/springframework/context/support/PropertySourcesPlaceholderConfigurer.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2022 the original author or authors.
+ * Copyright 2002-2023 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -170,14 +170,16 @@ public String getProperty(String key) {
 			}
 		}
 
-		processProperties(beanFactory, getPropertyResolver(this.propertySources));
+		processProperties(beanFactory, createPropertyResolver(this.propertySources));
 		this.appliedPropertySources = this.propertySources;
 	}
 
 	/**
-	 * Construct and provide a PropertyResolver from the given properties.
+	 * Create a {@link ConfigurablePropertyResolver} for the specified property sources.
+	 * @param propertySources the property sources to use
+	 * @since 6.0.12
 	 */
-	public ConfigurablePropertyResolver getPropertyResolver(MutablePropertySources propertySources){
+	protected ConfigurablePropertyResolver createPropertyResolver(MutablePropertySources propertySources){
 		return new PropertySourcesPropertyResolver(propertySources);
 	}