Remove Event::Shown and Event::Hidden

Their behaviour seems platform-specific, and they're only consistently triggered via code rather than user interactions, so there's not a lot of point to having them.

Author: 17cupsofcoffee

src/lifecycle.rs

@@ -62,19 +62,6 @@ pub enum Event {
         height: i32,
     },
 
-    /// The game window was shown.
-    ///
-    /// This event will fire once at startup. It will not be fired again
-    /// subsequently unless [`window::set_visible`](crate::window::set_visible)
-    /// is called.
-    Shown,
-
-    /// The game window was hidden.
-    ///
-    /// This event will only fire if [`window::set_visible`](crate::window::set_visible)
-    /// is called.
-    Hidden,
-
     /// The game window was restored to normal size and position by the user, either by
     /// un-minimizing or un-maximizing.
     Restored,

src/platform/window_sdl.rs

@@ -427,14 +427,6 @@ where
                     state.event(ctx, Event::Resized { width, height })?;
                 }
 
-                WindowEvent::Shown => {
-                    state.event(ctx, Event::Shown)?;
-                }
-
-                WindowEvent::Hidden => {
-                    state.event(ctx, Event::Hidden)?;
-                }
-
                 WindowEvent::Restored => {
                     state.event(ctx, Event::Restored)?;
                 }