Fix keybindings help and add minimize keybinding

rc.lua

@@ -364,15 +364,19 @@ clientkeys = gears.table.join(
     -- tiling
     awful.key({modkey,}, "Right",
         tiling.key.tileRight,
-        {description = "Move right", group = "window_tiling"}
+        {description = "Tile right", group = "tiling"}
     ),
     awful.key({modkey,}, "Left",
         tiling.key.tileLeft,
-        {description = "Move left", group = "window_tiling"}
+        {description = "Tile left", group = "tiling"}
     ),
     awful.key({modkey,}, "Up",
         tiling.key.toggleMaximized,
-        {description = "Move left", group = "window_tiling"}
+        {description = "Toggle maximized", group = "tiling"}
+    ),
+    awful.key({modkey,}, "Down",
+        tiling.key.minimize,
+        {description = "Lower", group = "tiling"}
     ),
 
     awful.key({ modkey,           }, "f",

tiling.lua

@@ -62,6 +62,9 @@ return {
                     c.maximized = false
                 end
             end
+        end,
+        minimize = function(c) 
+            c.minimized = true
         end
     }
 }