Datatype mismatch warning in logical replication when creating subscription

>
> Hi ,

> I’ve been exploring logical replication and noticed that if the column
> datatypes don’t match between the publisher and subscriber, PostgreSQL
> doesn’t give a warning. This can cause unexpected behavior, and I thought
> it might be helpful to alert users when this happens.

**What This Patch Does:**

> - Adds a warning when a column's datatype in the subscriber doesn’t match
> the publisher.

- Helps users catch issues early instead of running into silent errors
> later.

> Why I Think It’s Useful:- Avoids confusion when replication doesn’t
> work as expected. - Makes debugging easier by pointing out potential
> problems. I’d love to get feedback on whether this is a good
> idea and if I’ve approached it correctly. Since I’m still learning, any
> suggestions for improvement would be really helpful. I’ve attached the
> patch—please let me know what you think!

> Thanks, Blessy