wire: derive message id from position

wire/wl_keyboard.txt

@@ -1,36 +1,36 @@
 # requests
 
-request release = 0 {
+request release {
 
 }
 
 # events
 
-event keymap = 0 {
+event keymap {
     format: u32,
     fd: fd,
     size: u32,
 }
 
-event enter = 1 {
+event enter {
     serial: u32,
     surface: id(wl_surface),
     keys: array(u32),
 }
 
-event leave = 2 {
+event leave {
     serial: u32,
     surface: id(wl_surface),
 }
 
-event key = 3 {
+event key {
     serial: u32,
     time: u32,
     key: u32,
     state: u32,
 }
 
-event modifiers = 4 {
+event modifiers {
     serial: u32,
     mods_depressed: u32,
     mods_latched: u32,
@@ -38,7 +38,7 @@ event modifiers = 4 {
     group: u32,
 }
 
-event repeat_info = 5 {
+event repeat_info {
     rate: i32,
     delay: i32,
 }