Percentages and ratios #277

Hello, thanks a lot for this great package !
If I'm not mistaken there is no feature yet to humanize a ratio (between 0 and 1) or a percentage (between 0-100).

It could be a great addition ! It can be just one function to handle both, with two possible inputs (ratio= or percent=). The outcome would in both cases, be a truncated percent string with optional decimal coma up to a given precision, as in 12,5%. Customization of precision with a number of decimal could be similar to precisedelta's precision customization with the units.