Show function's alias name in the output column

### Is your feature request related to a problem or challenge?

When executing `select date_format(values, patterns) from t`, people often expect the output column to be named with the function name `date_format`. However, the actual is `to_char`:

https://github.com/apache/datafusion/blob/9942ecd4ac791c26546db8d8bf6ae674006a49fc/datafusion-examples/examples/date_time_functions.rs#L486-L505

This might cause some confusion, if people don't know `date_format` is aliased to `to_char`, and brings poor experience.

### Describe the solution you'd like

As title, instead of showing the actual executing function's name("`to_char`"), showing its alias("`date_format`").

### Describe alternatives you've considered

_No response_

### Additional context

_No response_