Fix the Java example code for Lists using RPUSH

[sanaulla123]

In the example under Capped List on the documentation page: https://redis.io/docs/latest/develop/data-types/lists/
The Java-Sync library code example is not matching the one given in Redis CLI and also not matching the problem statement: "For example, if you're adding bikes on the end of a list of repairs, but only want to worry about the 3 that have been on the list the longest:"

The right solution is to use rpush and ltrim the first X elements.

This PR fixes the code to match the Redis CLI example.

[sazzad16]

@sanaulla123 Thank you for noticing.

@andy-stark-redis No other examples match with redis-cli example.

If you confirm, we can merge this PR. If you want to fix differently, let us know.