Removed unnecessary bytemuck usage

This was copy-pasted from a Buffer<T> implementation that was removed
from Kludgine, since Buffer<T> isn't public.

Cargo.lock

@@ -574,7 +574,6 @@ dependencies = [
  "ahash",
  "alot",
  "arboard",
- "bytemuck",
  "cushy-macros",
  "figures",
  "image",

Cargo.toml

@@ -40,7 +40,6 @@ arboard = "3.2.1"
 zeroize = "1.6.1"
 unicode-segmentation = "1.10.1"
 pollster = "0.3.0"
-bytemuck = "1.14.0"
 
 
 # [patch.crates-io]

src/window.rs

@@ -2774,8 +2774,7 @@ where
             Ok(())
         })?;
 
-        self.data
-            .extend_from_slice(bytemuck::cast_slice(&slice.get_mapped_range()));
+        self.data.extend_from_slice(&slice.get_mapped_range());
 
         Format::convert_rgba(&mut self.data, render_size.width.get(), bytes_per_row);