[styles] allow from and to to be waivers

[JanMarvin]

This allows the following, came across this in the following SO. The issue at hand is that the first evaluation sets the current_sheet() no matter what the actual current sheet is.

I was considering updating the waiver code to add an argument or something similar, but there are not that many functions that take two potential sheets (clone worksheet and the one fixed here)

library(openxlsx2)

df <- data.frame(
  Date = Sys.Date() - 0:4, 
  Logical = c(TRUE, FALSE, TRUE, TRUE, FALSE),
  Currency = paste("$", -2:2),
  Accounting = -2:2,
  hLink = "https://CRAN.R-project.org/",
  Percentage = seq(-1, 1, length.out = 5), 
  TinyNumber = runif(5)/1e+09,
  stringsAsFactors = FALSE
)

dat_grouped <- df %>% dplyr::group_by(Date)

wb <- wb_workbook()$
  # first worksheet
  add_worksheet("1st")$
  add_data_table(x = dat_grouped, 
                 table_style = "TableStyleLight13")$
  set_col_widths(cols = "A:G", widths = c(10, 10, 10, 10, 25, 10, 10))$
  # second worksheet
  add_worksheet("2nd")$
  add_data_table(x = dat_grouped, 
                 table_style = "TableStyleLight13")$
  clone_sheet_style(from = "1st", to = openxlsx2::current_sheet())
  
if (interactive()) wb$open()