Improve grammar

wiki/src/doc/first_steps/introduction_to_gnome_and_the_tails_desktop.mdwn

@@ -227,7 +227,7 @@ button to lock your screen with a password.
 Click on the [[!img lib/media-playback-pause.png alt="Suspend" class="symbolic" link="no"]]
 button to suspend your computer.
 
-When suspended, your computer is not computing anymore but is still powered on,
+While suspended, your computer is not computing anymore but is still powered on,
 like if it was standing still but still alive.
 
 To resume from suspend and go back to the Tails desktop, push the power button