Format to significant digits

Usage

format_signif(x, digits = 3, max_small = 6, max_big = 6, keep_big = digits)

x: the numbers to format
digits: how many significant digits to show
max_small: maximum number of decimals to show before using scientific notation
max_big: maximum number of places to show (for large numbers) before using scientific notation
keep_big: number of significant digits to show when using scientific notation for large numbers