Note when setting node state power up/down happens

The power up/down request only takes effect after the ResumeTimeout
or SuspendTimeout is reached in order to avoid a race condition.

doc/man/man1/scontrol.1

@@ -936,7 +936,9 @@ Setting a node "DOWN" will cause all running and suspended jobs on that
 node to be terminated.
 "POWER_DOWN" and "POWER_UP" will use the configured \fISuspendProg\fR and
 \fIResumeProg\fR programs to explicitly place a node in or out of a power
-saving mode.
+saving mode. If a node is already in the process of being powered up or down,
+the command will have no effect until the configured ResumeTimeout or
+SuspendTimeout is reached.
 The "NoResp" state will only set the "NoResp" flag for a node without
 changing its underlying state.
 While all of the above states are valid, some of them are not valid new