Rename $apply() and $map() to $map_elements() and $map_batches()

[etiennebacher]

Close #512

We haven't implemented $apply() for DataFrame or Groupby yet. I also cleaned the docs of both methods.

[sorhawell]

Feel free to drop any example from map/apply you don't see necessary. Some of these examples I think take a little too long to run CI-wise.

[etiennebacher]

Some of these examples I think take a little too long to run CI-wise.

Yes but they are still useful I think, maybe I'll move them in a "tips and tricks" vignette with your examples for $transpose()

[etiennebacher]

@eitsupi sorry I forgot again, should I bump r-polars version in cargo.toml to 0.36.0 or 0.35.1? (I did 0.36.0 for now)

[eitsupi]

Actually, we are only looking at different version numbers here, so it should not be the same number, but 0.35.1 is a good choice to match the minor version of rust-polars.

r-polars/dev/generate-lib-sums.R

Line 32 in 2fbf67d

if (identical(current_lib_version, latest_released_lib_version)) {

[eitsupi]

Thanks!