Expanded Msaa documentation. (#3693)

- Added default value.
- Links to the explanation of Msaa on wikipedia.
- Added a short example to show how to use the struct on an app.

Fixes #3167.

crates/bevy_render/src/view/mod.rs

@@ -40,9 +40,22 @@ impl Plugin for ViewPlugin {
 }
 
 #[derive(Clone)]
+/// Configuration resource for [Multi-Sample Anti-Aliasing](https://en.wikipedia.org/wiki/Multisample_anti-aliasing).
+///
+/// # Example
+/// ```
+/// # use bevy_app::prelude::App;
+/// # use bevy_render::prelude::Msaa;
+/// App::new()
+///     .insert_resource(Msaa { samples: 4 })
+///     .run();
+/// ```
 pub struct Msaa {
     /// The number of samples to run for Multi-Sample Anti-Aliasing. Higher numbers result in
-    /// smoother edges. Note that WGPU currently only supports 1 or 4 samples.
+    /// smoother edges.
+    /// Defaults to 4.
+    ///
+    /// Note that WGPU currently only supports 1 or 4 samples.
     /// Ultimately we plan on supporting whatever is natively supported on a given device.
     /// Check out this issue for more info: <https://github.com/gfx-rs/wgpu/issues/1832>
     /// It defaults to 1 in wasm - <https://github.com/gfx-rs/wgpu/issues/2149>