Documentation Fix

Hi,
While going through the documentation, i saw 2 mistakes in documentation (https://pulsar.apache.org/docs/next/concepts-messaging/ ). Please recheck and correct it if highlighted is a mistake.

The non-partitioned topic 1 and non-partitioned topic 4 are assigned to consumer B. Consumer A is their stand-by consumer --> The non-partitioned topic 1 and non-partitioned topic 4 are assigned to consumer **A**. Consumer **B** is their stand-by consumer

The non-partitioned topic 2 and non-partitioned topic 3 are assigned to consumer A. Consumer B is their stand-by consumer. --> The non-partitioned topic 2 and non-partitioned topic 3 are assigned to consumer **B**. Consumer **A** is their stand-by consumer.

Open the concepts-messaging documentation page linked in the issue and locate the two descriptions of non-partitioned topics and standby consumers. Verify the consumer assignments against the surrounding diagram or explanation, correct the two statements, and confirm the page consistently identifies consumers A and B.

Written by the indexing model from the issue text.