Typo - Chapter 11 - Asynchronous Programming

[PolarisTLX]

I believe this is just a tiny typo but thought you'd want to have them corrected:

In Chapter 11, about 1/5th way down, in Callbacks section:

"The example adds support for "note" requests, which just   sends   a note to a given nest."

[marijnh]

Thanks for opening an issue! Fixed in attached patch.