[PATCH] Documentation/sysrq.txt: added short description for 'Q' (timerlist)

I added the 'Q' to list. A short description in the `Ok, so what can I
use them for'-section, on when or why to use it would be nice!
Signed-off-by: NJohannes Weiner <hannes-kernel@saeurebad.de>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Documentation/sysrq.txt

@@ -93,6 +93,8 @@ On all -  write a character to /proc/sysrq-trigger.  e.g.:
 
 'p'     - Will dump the current registers and flags to your console.
 
+'q'     - Will dump a list of all running timers.
+
 'r'     - Turns off keyboard raw mode and sets it to XLATE.
 
 's'     - Will attempt to sync all mounted filesystems.