Consider adding .by to ww_multi_scale()

[mikemahoney218]

dplyr functions (including summarise() and mutate(), among others) now have an argument, .by, which allows for per-operation grouping, removing the need for group_by() in simple pipelines. It'd be nice for ww_multi_scale() to support the same (for the sf method; raster methods don't support grouping, and probably never will), such that these calls were equivalent:

ww_multi_scale(
      dplyr::group_by(ames_sf, Neighborhood),
      Sale_Price,
      predictions,
      n = list(
        c(10, 10),
        c(1, 1)
      ),
      square = FALSE
    )

ww_multi_scale(
      ames_sf,
      Sale_Price,
      predictions,
      n = list(
        c(10, 10),
        c(1, 1)
      ),
      square = FALSE,
    .by = Neighborhood
    )

For what it's worth, note that dplyr errors when trying to mix group_by() and .by:

> dplyr::group_by(iris, Species) |> dplyr::summarise(m = mean(Sepal.Length), .by = Species)
Error in `dplyr::summarise()`:
! Can't supply `.by` when `.data` is a grouped data frame.
Run `rlang::last_trace()` to see where the error occurred.