[Minor] add debug info in optimizer.rs

[Ted-Jiang]

Which issue does this PR close?

it's better output which rule is running in debug log.
I got confused when debugging optimizer.
Closes #.

Rationale for this change

What changes are included in this PR?

Are there any user-facing changes?

[alamb]

Thanks @Ted-Jiang

You probably know it, but you can also use EXPLAIN VERBOSE to see the output of the plans after each pass

For example:

EXPLAIN VERBOSE SELECT * from foo where x > 5

[waynexia]

These logs are useful to me. They are exactly what I add when debugging #2712 🤣 (some panicking rules cannot benefit from EXPLAIN)

[Ted-Jiang]

Thanks @Ted-Jiang

You probably know it, but you can also use EXPLAIN VERBOSE to see the output of the plans after each pass

For example:

EXPLAIN VERBOSE SELECT * from foo where x > 5

@alamb Thanks a lot for your kindly advice! Like @waynexia said, our team send logical plan to datafusion, it's easy to debug in this way.(Not want change our code 😂)

[alamb]

Makes sense -- I just wanted to point out the EXPLAIN VERBOSE thing too