Layer-shell: Update protocol to match wlroots

Signed-off-by: Harish Krupo <harishkrupo@gmail.com>

protocol/wlr-layer-shell-unstable-v1.xml

@@ -140,7 +140,7 @@
         how they should interact with surfaces that do. If set to zero, the
         surface indicates that it would like to be moved to avoid occluding
         surfaces with a positive excluzive zone. If set to -1, the surface
-        indicates that it would not like to be moved to accomodate for other
+        indicates that it would not like to be moved to accommodate for other
         surfaces, and the compositor should extend it all the way to the edges
         it is anchored to.
 
@@ -191,6 +191,18 @@
       <arg name="keyboard_interactivity" type="uint"/>
     </request>
 
+    <request name="get_keyboard_modifiers">
+      <description summary="requests keyboard modifier events">
+        Keyboard modifier events would be sent to the client when need_events
+        is set to 1. Useful when the client wants to know about the current
+        layout.
+
+        Events is double-buffered, see wl_surface.commit.
+      </description>
+      <arg name="need_events" type="uint"/>
+      <arg name="seat" type="object" interface="wl_seat" allow-null="true"/>
+    </request>
+
     <request name="get_popup">
       <description summary="assign this layer_surface as an xdg_popup parent">
         This assigns an xdg_popup's parent to this layer_surface.  This popup