[DOC] Update math expression documentation #5312

Is your feature request related to a problem or challenge? Please describe what you are trying to do.
Documentation change

Describe the solution you'd like
We need to update doc https://github.com/apache/arrow-datafusion/blob/main/docs/source/user-guide/expressions.md highlighting the math functions works in sync with Rust math functions, but not the same as other SQL engines like PostreSQL. Need to provide examples from #5259

Describe alternatives you've considered
Not doing this

Additional context
By comments from #5259 (comment)