Add modifier for centering a view horizontally

Sources/Adwaita/View/Modifiers/View+.swift

@@ -14,4 +14,11 @@ extension View {
             .valign(.center)
     }
 
+    /// Wrap the view in a horizontal stack and center horizontally.
+    /// - Returns: The view.
+    public func horizontalCenter() -> View {
+        HStack { self }
+            .halign(.center)
+    }
+
 }

user-manual/Information/Widgets.md

@@ -59,6 +59,7 @@ This is an overview of the available widgets and other components in _Adwaita_.
 | `insensitive(_:)`                 | Make a view unable to detect actions. This is especially useful for overlays.           |
 | `onClick(handler:)`               | Run a function when the user clicks on the widget.                                      |
 | `verticalCenter()`                | Wrap a view in a `VStack` and center vertically.                                        |
+| `horizontalCenter()`              | Wrap a view in an `HStack` and center horizontally.                                     |
 
 ### `Button` Modifiers
 | Syntax                       | Description                                                                             |