Merge KeyEventExtra into KeyEvent (#4029)

To make the fields easier to use, and to allow constructing KeyEvent in
user test code.

src/platform_impl/orbital/mod.rs

@@ -2,12 +2,9 @@
 
 use std::{fmt, str};
 
-use smol_str::SmolStr;
-
 pub(crate) use self::event_loop::{ActiveEventLoop, EventLoop};
 pub use self::window::Window;
 use crate::dpi::PhysicalPosition;
-use crate::keyboard::Key;
 use crate::monitor::VideoMode;
 
 mod event_loop;
@@ -160,9 +157,3 @@ impl MonitorHandle {
         std::iter::empty()
     }
 }
-
-#[derive(Debug, Clone, Eq, PartialEq, Hash)]
-pub struct KeyEventExtra {
-    pub key_without_modifiers: Key,
-    pub text_with_all_modifiers: Option<SmolStr>,
-}