blackbox: fix long help text lines

package/blackbox/Config.in

@@ -2,6 +2,7 @@ config BR2_PACKAGE_BLACKBOX
 	bool "blackbox"
 	depends on BR2_PACKAGE_XORG||BR2_PACKAGE_XORG7
 	help
-	  Blackbox is a fast, lightweight window manager for the X Window System.
+	  Blackbox is a fast, lightweight window manager for the X
+	  Window System.
 
 	  http://blackboxwm.sourceforge.net/