userguide: document 'fullscreen global'

diff --git a/docs/userguide b/docs/userguide
index 19410209a807dcf0d37a61acf1a9918f2494c951..d4fefafd21e701fb09bffb66117c523cebdce81b 100644 (file)
--- a/docs/userguide
+++ b/docs/userguide
@@ -89,7 +89,7 @@ To display a window in fullscreen mode or to go out of fullscreen mode again,
 press +mod+f+.
 
 There is also a global fullscreen mode in i3 in which the client will span all
-available outputs.
+available outputs (the command is +fullscreen global+).
 
 === Opening other applications