Deprecate methodIdentification() in CacheAspectSupport for removal

CacheAspectSupport currently contains a protected methodIdentification()
method which is not used internally within the framework, and it appears
that it was accidentally copied from TransactionAspectSupport when the
caching support was first introduced.

In light of that, this commit deprecates it for removal in 7.1.

Closes gh-36576

spring-context/src/main/java/org/springframework/cache/interceptor/CacheAspectSupport.java

@@ -300,7 +300,9 @@ public abstract class CacheAspectSupport extends AbstractCacheInvoker
 	 * @param targetClass class the method is on
 	 * @return log message identifying this method
 	 * @see org.springframework.util.ClassUtils#getQualifiedMethodName
+	 * @deprecated since 6.2.18 with no replacement, for removal in 7.1
 	 */
+	@Deprecated(since = "6.2.18", forRemoval = true)
 	protected String methodIdentification(Method method, Class<?> targetClass) {
 		Method specificMethod = ClassUtils.getMostSpecificMethod(method, targetClass);
 		return ClassUtils.getQualifiedMethodName(specificMethod);