Correct two spelling errors

Author: apachezy

src/Wpf.Ui/Controls/ContentDialog/ContentDialog.FocusBehavior.cs

@@ -129,7 +129,7 @@ private bool IsFocusInsideDialogCore(IInputElement? element)
     /// <remarks>
     /// Priority strategy:
     /// 1. Content-first: focus the first focusable element within the user-provided
-    ///    `Content` (the first focusable `FrameworkElement`).
+    ///    `Content` (the first focusable `<see cref="Control"/>`).
     /// 2. Built-in default button: if a built-in template button (Primary, Close, or
     ///    Secondary) is marked as default and is safely focusable, focus it (see
     ///    <see cref="FocusBuiltInButton"/>).

src/Wpf.Ui/Controls/ContentDialog/ContentDialog.cs

@@ -617,7 +617,7 @@ public ContentPresenter? DialogHost
         {
             if (_dialogHostEx is not null)
             {
-                throw new InvalidOperationException("Cannot set DialogHost when Host is already set.");
+                throw new InvalidOperationException("Cannot set DialogHost when DialogHostEx is already set.");
             }
 
             if (IsShowing)