chore(docs): make changelogs visible on docsrs

Split changelog file to make it more comprehensible when reading and
also make it a part of documentation so it'll be more discoverable
by the users. This change also makes it possible for rust code inside
the changelogs to be tested with `cargo`.

Co-authored-by: Kirill Chibisov <contact@kchibisov.com>

src/changelog/v0.9.md

@@ -0,0 +1,22 @@
+## 0.9.0
+
+- Added event `WindowEvent::HiDPIFactorChanged`.
+- Added method `MonitorId::get_hidpi_factor`.
+- Deprecated `get_inner_size_pixels` and `get_inner_size_points` methods of `Window` in favor of
+`get_inner_size`.
+- **Breaking:** `EventsLoop` is `!Send` and `!Sync` because of platform-dependant constraints,
+  but `Window`, `WindowId`, `DeviceId` and `MonitorId` guaranteed to be `Send`.
+- `MonitorId::get_position` now returns `(i32, i32)` instead of `(u32, u32)`.
+- Rewrite of the wayland backend to use wayland-client-0.11
+- Support for dead keys on wayland for keyboard utf8 input
+- Monitor enumeration on Windows is now implemented using `EnumDisplayMonitors` instead of
+`EnumDisplayDevices`. This changes the value returned by `MonitorId::get_name()`.
+- On Windows added `MonitorIdExt::hmonitor` method
+- Impl `Clone` for `EventsLoopProxy`
+- `EventsLoop::get_primary_monitor()` on X11 will fallback to any available monitor if no primary is found
+- Support for touch event on wayland
+- `WindowEvent`s `MouseMoved`, `MouseEntered`, and `MouseLeft` have been renamed to
+`CursorMoved`, `CursorEntered`, and `CursorLeft`.
+- New `DeviceEvent`s added, `MouseMotion` and `MouseWheel`.
+- Send `CursorMoved` event after `CursorEntered` and `Focused` events.
+- Add support for `ModifiersState`, `MouseMove`, `MouseInput`, `MouseMotion` for emscripten backend.