Add Direction2d::from_xy and Direction3d::from_xyz (#10882)

# Objective

Make direction construction a bit more ergonomic.

## Solution

Add `Direction2d::from_xy` and `Direction3d::from_xyz`, similar to
`Transform::from_xyz`:

```rust
let dir2 = Direction2d::from_xy(0.5, 0.5).unwrap();
let dir3 = Direction3d::from_xyz(0.5, 0.5, 0.5).unwrap();
```

This can be a bit cleaner than using `new`:

```rust
let dir2 = Direction2d::new(Vec2::new(0.5, 0.5)).unwrap();
let dir3 = Direction3d::new(Vec3::new(0.5, 0.5, 0.5)).unwrap();
```

Author: Jondolf

crates/bevy_math/src/primitives/dim2.rs

@@ -28,7 +28,15 @@ impl Direction2d {
         )
     }
 
-    /// Create a direction from a [`Vec2`] that is already normalized
+    /// Create a direction from its `x` and `y` components.
+    ///
+    /// Returns [`Err(InvalidDirectionError)`](InvalidDirectionError) if the length
+    /// of the vector formed by the components is zero (or very close to zero), infinite, or `NaN`.
+    pub fn from_xy(x: f32, y: f32) -> Result<Self, InvalidDirectionError> {
+        Self::new(Vec2::new(x, y))
+    }
+
+    /// Create a direction from a [`Vec2`] that is already normalized.
     pub fn from_normalized(value: Vec2) -> Self {
         debug_assert!(value.is_normalized());
         Self(value)

crates/bevy_math/src/primitives/dim3.rs

@@ -28,7 +28,15 @@ impl Direction3d {
         )
     }
 
-    /// Create a direction from a [`Vec3`] that is already normalized
+    /// Create a direction from its `x`, `y`, and `z` components.
+    ///
+    /// Returns [`Err(InvalidDirectionError)`](InvalidDirectionError) if the length
+    /// of the vector formed by the components is zero (or very close to zero), infinite, or `NaN`.
+    pub fn from_xyz(x: f32, y: f32, z: f32) -> Result<Self, InvalidDirectionError> {
+        Self::new(Vec3::new(x, y, z))
+    }
+
+    /// Create a direction from a [`Vec3`] that is already normalized.
     pub fn from_normalized(value: Vec3) -> Self {
         debug_assert!(value.is_normalized());
         Self(value)