Fix various typos

Mainly fix typos in comments, but also some minor code changes:

* Rename `apply_on_poiner` to `apply_on_pointer`.
* Rename `ImeState::Commited` to `ImeState::Committed`
* Correct `cfg_attr` usage: `wayland_platfrom` -> `wayland_platform`.

src/platform_impl/ios/mod.rs

@@ -85,7 +85,7 @@ pub(crate) use crate::platform_impl::Fullscreen;
 
 /// There is no way to detect which device that performed a certain event in
 /// UIKit (i.e. you can't differentiate between different external keyboards,
-/// or wether it was the main touchscreen, assistive technologies, or some
+/// or whether it was the main touchscreen, assistive technologies, or some
 /// other pointer device that caused a touch event).
 #[derive(Debug, Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
 pub struct DeviceId;