Clean up some logic around the RunState resource

chapter-07-damage/src/main.rs

@@ -51,11 +51,7 @@ impl State {
 impl GameState for State {
     fn tick(&mut self, ctx: &mut Rltk) {
         ctx.cls();
-        let mut newrunstate;
-        {
-            let runstate = self.ecs.fetch::<RunState>();
-            newrunstate = *runstate;
-        }
+        let mut newrunstate = *self.ecs.fetch::<RunState>();
 
         match newrunstate {
             RunState::PreRun => {
@@ -74,11 +70,7 @@ impl GameState for State {
                 newrunstate = RunState::AwaitingInput;
             }
         }
-
-        {
-            let mut runwriter = self.ecs.write_resource::<RunState>();
-            *runwriter = newrunstate;
-        }
+        *self.ecs.write_resource() = newrunstate;
         damage_system::delete_the_dead(&mut self.ecs);
 
         draw_map(&self.ecs, ctx);