isbounded() and isunbounded() are not exported

[LakshyaKhatri]

Thanks @omus for a quick response on the previous issue. Also, in the API section (Intervals.span — Function) I have two doubts:

1. The isbounded and isunbounded functions are not exported. Is that the expected behaviour? If so, it will be helpful to mention that in the docs.
2. Is that trailing ( ` ) intentional in the second snippet?
   

Feel free to close the issue if this is expected.

[omus]

Thanks for the issue. At the moment isbounded and isunbounded aren't exported as we will be changing isopen to no longer be exported (see #100)

The extra backtick is incorrect and should be corrected