* Document `-d:asyncBackend` flag
Since libraries may want to support multiple async backends, it's useful
to standardize the way this is done, so as to simplify usage of any
async backend within the ecosystem.
A similar text is being added to chronos here:
https://github.com/status-im/nim-chronos/pull/216
See also https://github.com/status-im/nim-chronos/issues/207
* typos, add none
* Update lib/pure/asyncdispatch.nim
* Update lib/pure/asyncdispatch.nim
Co-authored-by: Andreas Rumpf <rumpf_a@web.de>
0635697a89