Lint vertical spacing in the code (#3224)

* Lint vertical spacing in the code

* Add some vertical spacing for readability

crates/epaint/src/textures.rs

@@ -9,8 +9,10 @@ use crate::{ImageData, ImageDelta, TextureId};
 pub struct TextureManager {
     /// We allocate texture id:s linearly.
     next_id: u64,
+
     /// Information about currently allocated textures.
     metas: ahash::HashMap<TextureId, TextureMeta>,
+
     delta: TexturesDelta,
 }