Clarify the semantic of lite mode

This commit removes the "plain old class" bit of the documentation as
it may be confusing. The gist of it is that it must be a bean but not
annotated with `@Configuration` so the updated sentence states exactly
that.

Closes gh-29957

spring-context/src/main/java/org/springframework/context/annotation/Bean.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2021 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.
@@ -135,9 +135,9 @@ import org.springframework.core.annotation.AliasFor;
  * <h3>{@code @Bean} <em>Lite</em> Mode</h3>
  *
  * <p>{@code @Bean} methods may also be declared within classes that are <em>not</em>
- * annotated with {@code @Configuration}. For example, bean methods may be declared
- * in a {@code @Component} class or even in a <em>plain old class</em>. In such cases,
- * a {@code @Bean} method will get processed in a so-called <em>'lite'</em> mode.
+ * annotated with {@code @Configuration}. If a bean methods is declared on a bean
+ * that is <em>not</em> annotated with {@code @Configuration} it is processed in a
+ * so-called <em>'lite'</em> mode.
  *
  * <p>Bean methods in <em>lite</em> mode will be treated as plain <em>factory
  * methods</em> by the container (similar to {@code factory-method} declarations