Custom dark/light theming

[simonpcouch]

The symbol.R file contains some functionality for custom logging colors:

tune/R/symbol.R

Lines 19 to 24 in f6300b1

	# To remove the crayon dependency, use the cli analogs. However, these
	# produce ansi_string objects and some of our logging code needs
	# the character values. Will not be needed for cli >= 2.1.0.9000
	yellow <- function(...) as.character(cli::col_yellow(...))
	black <- function(...) as.character(cli::col_black(...))
	white <- function(...) as.character(cli::col_white(...))

Initiated in .onLoad():

tune/R/zzz.R

Lines 38 to 39 in f6300b1

	makeActiveBinding(
	"tune_color",

In the time since this code written, cli has matured greatly. I'd urge us to consider deprecating the tune_color active binding in .onLoad() in favor of cli's palette infrastructure.