Rename label_dollar to label_currency

[pwseo]

Shouldn't label_dollar be renamed label_currency? I know it is functionally the same, but such a name would instantly tell the programmer that multiple currencies are probably supported, prompting one to read the documentation on how to specify them, instead of searching (for example) for a label_euro.

[clauswilke]

I fully agree with this comment. I taught this recently in the classroom and it was clear that the students were very confused when I was using a function label_dollar to create all sorts of different labels.

[olivroy]

I think this is great. Maybe it would be great that label_currency() to be locale dependant (like label_date() that creates the scales in your system's language by default

[thomasp85]

@olivroy I don't think that is a good idea as it is much more normal to work with data in a currency that is not your own compared to using a date format different from your locale