go spec: clarification of channel close()

R=r, rsc
CC=golang-dev
https://golang.org/cl/1766042

doc/go_spec.html

 <!-- title The Go Programming Language Specification -->
-<!-- subtitle Version of July 12, 2010 -->
+<!-- subtitle Version of July 14, 2010 -->
 
 <!--
 TODO
@@ -4347,14 +4347,17 @@ BuiltinArgs = Type [ "," ExpressionList ] | ExpressionList .
 <h3 id="Close_and_closed">Close and closed</h3>
 
 <p>
-For a channel <code>c</code>, the predefined function <code>close(c)</code>
-marks the channel as unable to accept more
-values through a send operation.  After any previously
+For a channel <code>c</code>, the built-in function <code>close(c)</code>
+marks the channel as unable to accept more values through a send operation;
+values sent to a closed channed are ignored.
+After calling <code>close</code>, and after any previously
 sent values have been received, receive operations will return
-the zero value for the channel's type.  After at least one such zero value has been
+the zero value for the channel's type without blocking.
+After at least one such zero value has been
 received, <code>closed(c)</code> returns true.
 </p>
 
+
 <h3 id="Length_and_capacity">Length and capacity</h3>
 
 <p>
@@ -4560,10 +4563,10 @@ func recover() interface{}
 </pre>
 
 <p>
-<font color=red>TODO: Most of this text could move to the respective
+<span class="alert">TODO: Most of this text could move to the respective
 comments in <code>runtime.go</code> once the functions are implemented.
 They are here, at least for now, for reference and discussion.
-</font>
+</span>
 </p>
 
 <p>