Update documentation to make it clear that recurring tasks only take numerals, not spelled numbers

[snitkofb]

I got tripped up thinking that I could not make a task recur "every other month" or "every two months," but the plug in can. The software only supports "every 2 months" or "every 3 weeks." An update would be great (I've never really programmed in javascript, so I'm not that helpful here). But a note in the documentation would probably be sufficient.

[claremacrae]

Hi, thank you for using tasks.

Please could you go to the Issues panel, and click New, and then create a new Feature Request there?

We are no longer tracking feature requests via discussions (which is why this category is now called Ideas: Any New Feature Requests go in Issues please).

Many thanks.

Clare