Styles functions to accept logical and numeric

[JanMarvin]

At the moment we only accept characters in cases where logicals or numerics would feel more natural to users.

Using a wb_add_font() example:

library(openxlsx2)
wb <- wb_workbook() %>% wb_add_worksheet("S1") %>% wb_add_data("S1", mtcars)

# This works and is documented
wb <- wb %>% wb_add_font("S1", "A1:K1", name = "Arial", bold = "1", size = "14")

# This should work too
wb <- wb %>% wb_add_font("S1", "A2:K2", name = "Arial", bold = TRUE, size = 14)
#> Error in eval(expr, envir, enclos): Expecting a string vector: [type=NULL; required=STRSXP].

We have to identify cases where logicals and numerics can be used as substitutes and wrap the content if not character and not NULL.