chore: Fix several style lints (#17488)

It's not comprehensive enough to start linting on `style` group, but
hey, it's a start.

Release Notes:

- N/A

crates/gpui/examples/animation.rs

@@ -9,7 +9,7 @@ impl AssetSource for Assets {
         std::fs::read(path)
             .map(Into::into)
             .map_err(Into::into)
-            .map(|result| Some(result))
+            .map(Some)
     }
 
     fn list(&self, path: &str) -> Result<Vec<SharedString>> {
@@ -23,7 +23,7 @@ impl AssetSource for Assets {
     }
 }
 
-const ARROW_CIRCLE_SVG: &'static str = concat!(
+const ARROW_CIRCLE_SVG: &str = concat!(
     env!("CARGO_MANIFEST_DIR"),
     "/examples/image/arrow_circle.svg"
 );

crates/gpui/examples/input.rs

@@ -298,9 +298,7 @@ impl ViewInputHandler for TextInput {
         bounds: Bounds<Pixels>,
         _cx: &mut ViewContext<Self>,
     ) -> Option<Bounds<Pixels>> {
-        let Some(last_layout) = self.last_layout.as_ref() else {
-            return None;
-        };
+        let last_layout = self.last_layout.as_ref()?;
         let range = self.range_from_utf16(&range_utf16);
         Some(Bounds::from_corners(
             point(

crates/gpui/examples/opacity.rs

@@ -66,8 +66,6 @@ impl HelloWorld {
                     break;
                 }
             }
-
-            ()
         }));
     }
 }