config: support <margin top="" bottom="" left="" right="" output="" />

docs/labwc-config.5.scd

@@ -239,6 +239,12 @@ Therefore, where multiple objects of the same kind are required (for example
 *<theme><font place=""><weight>*
 	Font weight (normal or bold). Default is normal.
 
+## MARGIN
+
+*<margin top="" bottom="" left="" right="" output="" />*
+	Specify the number of pixels to reserve at the edges of an output.
+	New, maximized and tiled windows will not be placed in these areas.
+
 ## KEYBOARD
 
 *<keyboard><keybind key="">*

docs/rc.xml.all

@@ -93,6 +93,17 @@
     </names>
   </desktops>
 
+  <!--
+    # <margin> can be used to reserve space where new/maximized/tiled
+    # windows will not be placed. Clients using layer-shell protocol reserve
+    # space automatically, so <margin> is only intended for other, specialist
+    # cases.
+    #
+    # If output is left empty, the margin will be applied to all outputs.
+
+    <margin top="" bottom="" left="" right="" output="" />
+  -->
+
   <!-- Percent based regions based on output usable area, % char is required -->
   <!--
     <regions>