feature: Derive Hash for KeyboardInput. (#14263)

# Objective

Derive `Hash` for `KeyboardInput`.

## Problem

I was [writing code](cxreiff/bevy_ratatui#13) to
take `crossterm` events and republish them as bevy input events. One
scenario requires I check if the same key press was happening
repeatedly; in a regular terminal we don't get key released events, so I
was simulating them.

I was surprised to find that I couldn't put `KeyboardInput` into a
`HashSet`.

## Work Around

My work around was to add a new type that implemented Hash.

```rust
#[derive(Deref, DerefMut, PartialEq, Eq)]
struct KeyInput(KeyboardInput);

impl Hash for KeyInput {
    fn hash<H>(&self, state: &mut H)
    where
        H: Hasher,
    {
        self.key_code.hash(state);
        self.logical_key.hash(state);
        self.state.hash(state);
        self.window.hash(state);
    }
}
```

## Solution

A better solution since all members of `KeyboardInput` implement `Hash`
is to have it derive `Hash` as well.

## Testing

My newtype solution works for its purpose.

---------

Co-authored-by: Alice Cecile <[email protected]>
Co-authored-by: Josh McKinney <[email protected]>
Co-authored-by: BD103 <[email protected]>

Author: 4 people

crates/bevy_input/src/keyboard.rs

@@ -88,8 +88,12 @@ use bevy_reflect::{ReflectDeserialize, ReflectSerialize};
 ///
 /// The event is consumed inside of the [`keyboard_input_system`]
 /// to update the [`ButtonInput<KeyCode>`](ButtonInput<KeyCode>) resource.
-#[derive(Event, Debug, Clone, PartialEq, Eq)]
-#[cfg_attr(feature = "bevy_reflect", derive(Reflect), reflect(Debug, PartialEq))]
+#[derive(Event, Debug, Clone, PartialEq, Eq, Hash)]
+#[cfg_attr(
+    feature = "bevy_reflect",
+    derive(Reflect),
+    reflect(Debug, PartialEq, Hash)
+)]
 #[cfg_attr(feature = "serialize", derive(serde::Serialize, serde::Deserialize))]
 #[cfg_attr(
     all(feature = "serialize", feature = "bevy_reflect"),