More examples in docstrings

It would be very helpful if each macro/command had an example in the docstring.

For example, I've been having a lot of trouble using @rtranform to make a new column based on conditional aspects of other columns at the row level. The doctring in the REPL is:

help?> @rtransform
  @rtransform(x, args...)

  Row-wise version of @transform, i.e. all operations use @byrow by default. See @transform for details.

I didn't find the help I needed here, a good example would keep me moving along with my work.

I'm not a computer scientist, and its time-intensive to unravel how these excellent tools are implemented. I've invested time to apply julia in my work vs. the python ecosystem because of its great qualities, however the most consistent hurdle for me is the lack of examples.

Perhaps the usage is obvious to package developers, but for more pedestrian types like me nothing could be more illuminating than a good example.

Start with the docstrings for @rtransform and @transform, using the REPL help example in the issue as the entry point. Review the other macro and command docstrings to identify where examples are missing, then add clear usage examples for the relevant operations. Done means the documented macros and commands provide practical examples, including row-wise conditional column creation.