Other wordings are possible but defining this as one
of the ways to proceed means we don't have to add
language about this to the description of select.
Fixes #2825.
R=golang-dev, gri, r
CC=golang-dev
https://golang.org/cl/
5643062
<p>
Both the channel and the value expression are evaluated before communication
-begins. Communication blocks until the send can proceed, at which point the
-value is transmitted on the channel.
+begins. Communication blocks until the send can proceed.
A send on an unbuffered channel can proceed if a receiver is ready.
A send on a buffered channel can proceed if there is room in the buffer.
+A send on a closed channel proceeds by causing a <a href="#Run_time_panics">run-time panic</a>.
A send on a <code>nil</code> channel blocks forever.
</p>