doc refactor: timers

doc/api/timers.markdown

@@ -1,6 +1,9 @@
-## Timers
+# Timers
 
-### setTimeout(callback, delay, [arg], [...])
+All of the timer functions are globals.  You do not need to `require()`
+this module in order to use them.
+
+## setTimeout(callback, delay, [arg], [...])
 
 To schedule execution of a one-time `callback` after `delay` milliseconds. Returns a
 `timeoutId` for possible use with `clearTimeout()`. Optionally you can
@@ -11,16 +14,16 @@ It is important to note that your callback will probably not be called in exactl
 the callback will fire, nor of the ordering things will fire in. The callback will
 be called as close as possible to the time specified.
 
-### clearTimeout(timeoutId)
+## clearTimeout(timeoutId)
 
 Prevents a timeout from triggering.
 
-### setInterval(callback, delay, [arg], [...])
+## setInterval(callback, delay, [arg], [...])
 
 To schedule the repeated execution of `callback` every `delay` milliseconds.
 Returns a `intervalId` for possible use with `clearInterval()`. Optionally
 you can also pass arguments to the callback.
 
-### clearInterval(intervalId)
+## clearInterval(intervalId)
 
 Stops a interval from triggering.