Used internally (not exported) to apply all relevant formatting. It is
documented here only because it can be used when setting the
dfSummary.custom.1 and dfSummary.custom.1 options.
Usage
format_number(x, round.digits, ...)
Arguments
x
A numerical value to be formatted.
round.digits
Numerical. Number of decimals to show. Used to define
both digits and nsmall when calling format.
...
Any other formatting instruction that is compatible with
format.