Fix a typo "cant" to "can't" in client.c
--- a/client.c
+++ b/client.c
@@ -623,7 +623,7 @@
 
 	oldcc = client_current();
 
-	/* If no windows then you cant cycle */
+	/* If no windows then you can't cycle */
 	if (TAILQ_EMPTY(&sc->mruq))
 		return;
 
