Fix typo

examples/rust/custom_callback/README.md

@@ -1,5 +1,5 @@
 <!--[metadata]
-title = "Custom Viewer Callback"
+title = "Custom Viewer callback"
 thumbnail = "https://static.rerun.io/custom_callback/1434da408fd59ea1349169784b47d8ffc285022e/480w.png"
 thumbnail_dimensions = [480, 291]
 -->
@@ -25,7 +25,7 @@ This example is divided into two parts:
 - **App** ([`src/app.rs`](src/app.rs)): The application that uses the Rerun SDK.
 
 In the `app`, an additional TCP listener is opened to allow the `viewer` to send messages to the `app`.
-Similar to the [`extend_viewer_ui`](../extend_viewer_ui/) example, the `viewer` is wrapped in an `eframe` app, which allows us to handle the extra communication logic and define our own contorl UI using [`egui`](https://github.com/emilk/egui).
+Similar to the [`extend_viewer_ui`](../extend_viewer_ui/) example, the `viewer` is wrapped in an `eframe` app, which allows us to handle the extra communication logic and define our own control UI using [`egui`](https://github.com/emilk/egui).
 
 The communication between the `viewer` and the `app` is implemented in the [`comms`](src/comms/) module. It defines a simple protocol to send messages between the `viewer` and the `app` using [`bincode`](https://github.com/bincode-org/bincode).
 The protocol supports basic commands that the `viewer` can send to the `app`, such as logging a [`Boxes3D`](https://www.rerun.io/docs/reference/types/archetypes/boxes3d) or [`Point3D`](https://www.rerun.io/docs/reference/types/archetypes/points3d) to an entity, or changing the radius of a set of points that is being logged.