Re export where(), any_of(), all_of() + error early for absent footnote.

[olivroy]

Summary

The rationale for the footnote change is the following:

# Before
exibble %>% gt() %>% cols_hide(num) %>% tab_footnote(locations = cells_column_labels())
#> Error in `fun(..., .envir = .envir)`:
#> ! Could not evaluate cli `{}` expression: `footnote`.
#> Caused by error in `eval(expr, envir = envir)`:
#> ! l'argument "footnote" est manquant, avec aucune valeur par défaut

# This PR
exibble %>% gt() %>% cols_hide(num) %>% tab_footnote(locations = cells_column_labels())
#> Error in `tab_footnote()`:
#> ! `footnote` is absent but must be supplied.

The idea behind re-exporting tidyselect::where() is to facilitate making summary rows work out of the box.

For example, this will work without loading the tidyverse.

library(gt)
exibble |> gt() |> grand_summary_rows(columns = where(is.numeric), fns = "sum")

Checklist

• I understand and agree to the Code of Conduct.
• I have listed any major changes in the NEWS.
• I have added testthat unit tests to tests/testthat for any new functionality.

[rich-iannone]

LGTM!