doc/articles: rename concurrency patterns article

The old name, automatically generated, was ludicrously verbose.
Also clean up an example to use time.Second.

R=golang-dev, dsymonds
CC=golang-dev
https://golang.org/cl/5876051

doc/docs.html

@@ -105,7 +105,7 @@ Guided tours of Go programs.
 <li><a href="http://blog.golang.org/2010/04/json-rpc-tale-of-interfaces.html">JSON-RPC: a tale of interfaces</a></li>
 <li><a href="/doc/articles/gos_declaration_syntax.html">Go's Declaration Syntax</a></li>
 <li><a href="/doc/articles/defer_panic_recover.html">Defer, Panic, and Recover</a></li>
-<li><a href="/doc/articles/go_concurrency_patterns_timing_out_moving_on.html">Go Concurrency Patterns: Timing out, moving on</a></li>
+<li><a href="/doc/articles/concurrency_patterns.html">Go Concurrency Patterns: Timing out, moving on</a></li>
 <li><a href="/doc/articles/slices_usage_and_internals.html">Go Slices: usage and internals</a></li>
 <li><a href="http://blog.golang.org/2011/05/gif-decoder-exercise-in-go-interfaces.html">A GIF decoder: an exercise in Go interfaces</a></li>
 <li><a href="/doc/articles/error_handling.html">Error Handling and Go</a></li>

doc/progs/timeout1.go

@@ -11,7 +11,7 @@ func Timeout() {
 	ch := make(chan bool, 1)
 	timeout := make(chan bool, 1)
 	go func() {
-		time.Sleep(1e9) // one second
+		time.Sleep(1 * time.Second)
 		timeout <- true
 	}()