Advance unnamed `nest()` specification warning to defunct stage

[DavisVaughan]

i.e. this warning from here

tidyr/R/nest.R

Lines 146 to 149 in 71ec2d6

	cli::cli_warn(c(
	"All elements of `...` must be named.",
	i = "Did you want `{(.key)} = {cols_fixed_label}`?"
	))

nest(mtcars, -vs)
#> Warning: All elements of `...` must be named.
#> ℹ Did you want `data = -vs`?
#> # A tibble: 2 × 2
#>      vs data              
#>   <dbl> <list>            
#> 1     0 <tibble [18 × 10]>
#> 2     1 <tibble [14 × 10]>

This has been warning on every call since tidyr 1.0.0 in 2019, so we should be able to move this to defunct.

Last time we tried this (#1464), 5 packages failed. So we'd need to send them PRs to update.

• cubble
• highcharter
• HTSSIP
• T2Qv
• unpivotr