v5.5.3

Doc improvements and bug fixes ported from upstream raylib-rs, scoped to
soundness and correctness. Thanks to all the original authors linked below.

Breaking

• Image::export_image_to_memory now returns Result<Vec<u8>, Error> instead
  of Result<&[u8], Error>. The previous signature leaked on every call
  (raylib's buffer was never freed) and had an unsound lifetime. Adapted from
  raylib-rs #250 / #247.

Deprecated

• RaylibMesh::indicies / indicies_mut — use indices / indices_mut. The
  typo'd names stay through 5.x and are removed in 6.0.

Fixed

• Soundness: RaylibMesh accessors return an empty slice when the
  underlying buffer is null instead of invoking UB via
  slice::from_raw_parts(null, _) (raylib-rs#257).
• Soundness: RaylibMesh::indices length is now triangleCount * 3 (what
  raylib allocates) rather than vertexCount (raylib-rs#257).
• Soundness: Sound::alias lifetimes correctly bind the sound's lifetime to
  the receiver (4d53bd4).
• Use-after-free: load_model_animations frees only the outer array via
  MemFree, rather than UnloadModelAnimations which also tore down the
  animations the Vec had just taken ownership of (ccc0827).
• Data corruption: AudioStream::update passes element count (not byte
  size) to ffi::UpdateAudioStream, matching the C API
  (raylib-rs#212).
• Texture2D::update_texture_rec validates the destination rectangle and sizes
  the expected pixel buffer from rect dimensions (cb0c004).
• Closure-based draw helpers (draw, draw_mode2D, etc.) no longer call
  ffi::End*() twice — the handle's Drop already does
  (aadf1a7).
• gui_text_box and gui_text_input_box grow the buffer and round-trip the
  null terminator, so text input works (e2be94b).
• gui_panel passes a null pointer for empty strings, matching GuiPanel's C
  API (95234d1).

Other

• Add docs to README on drop ordering.
• CI and just ok build with --all-targets so examples are exercised
  alongside the library crates.
• Examples look better on High DPI screens.
• just examples to quickly run a bunch of different examples.