Docs: Feedback for Filtering Members with Attributes

[wyohm]

Hi, I have some feedback about this page

Wrong variable names used (second line looks like is should be fourCore.setAttribute() ):

        MemberAttributeConfig fourCore = new MemberAttributeConfig();
        memberAttributeConfig.setAttribute( "CPU_CORE_COUNT", "4" );

This section suggests using a method ( [HazelcastInstance](https://docs.hazelcast.org/docs/5.5.0/javadoc/com/hazelcast/core/HazelcastInstance.html).setAttribute() ) which does not exist.

        HazelcastInstance member4 = Hazelcast.newHazelcastInstance();
        // We can also set member attributes at runtime.
        member4.setAttribute( "CPU_CORE_COUNT", "2" );