On X11, extract event handlers

Make code more clear wrt explicit returns during event handling,
which may lead to skipped IME event handling.

src/platform_impl/linux/x11/atoms.rs

@@ -6,7 +6,7 @@ macro_rules! atom_manager {
     ($($name:ident $(:$lit:literal)?),*) => {
         x11rb::atom_manager! {
             /// The atoms used by `winit`
-            pub(crate) Atoms: AtomsCookie {
+            pub Atoms: AtomsCookie {
                 $($name $(:$lit)?,)*
             }
         }
@@ -14,7 +14,7 @@ macro_rules! atom_manager {
         /// Indices into the `Atoms` struct.
         #[derive(Copy, Clone, Debug)]
         #[allow(non_camel_case_types)]
-        pub(crate) enum AtomName {
+        pub enum AtomName {
             $($name,)*
         }