Russ Cox 4391aca850 doc/play: update URL for concurrent pi
The old link died; replace with an archive.org copy.

Fixes #13345.

Change-Id: Ic4a7fdcf258e1ff3b4a02ecb4f237ae7db2686c7
Reviewed-on: https://go-review.googlesource.com/18335
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2016-01-06 20:23:21 +00:00
..
2012-11-26 13:05:18 -08:00
2016-01-06 20:23:21 +00:00