Fix duplicate H1 warnings: msix publish-your-app files

Append 'for MSIX apps' to H1 headings to resolve duplicate-h1s build warnings.
These files have identical H1s to their pwa/ counterparts.

Co-authored-by: Copilot <[email protected]>

Author: GrantMeStrength

hub/apps/publish/publish-your-app/msix/create-app-submission.md

@@ -5,7 +5,7 @@ ms.topic: how-to
 ms.date: 08/21/2025
 ---
 
-# Create app submission
+# Create app submission for MSIX apps
 
 > [!NOTE]
 > This section of the documentation describes how to create an app submission in Partner Center. Alternatively, you can use the [Microsoft Store submission API](/windows/uwp/monetize/create-and-manage-submissions-using-windows-store-services) to automate app submissions.

hub/apps/publish/publish-your-app/msix/enter-app-properties.md

@@ -6,7 +6,7 @@ ms.topic: article
 ms.localizationpriority: medium
 ---
 
-# Enter app properties
+# Enter app properties for MSIX apps
 
 The **Properties** page of the [app submission process](./create-app-submission.md) is where you define your app's category and enter other info and declarations. Be sure to provide complete and accurate details about your app on this page.
 

hub/apps/publish/publish-your-app/msix/import-and-export-store-listings.md

@@ -6,7 +6,7 @@ ms.topic: article
 ms.localizationpriority: medium
 ---
 
-# Import and export store listings
+# Import and export store listings for MSIX apps
 
 Instead of [entering info for your Store listings directly in Partner Center](./add-and-edit-store-listing-info.md), you have the option to add or update info by exporting your listings in a .csv file, entering your info and assets, and then importing the updated file. You can use this method to create listings from scratch, or to update listings you’ve already created.
 

hub/apps/publish/publish-your-app/msix/manage-submission-options.md

@@ -6,7 +6,7 @@ ms.topic: how-to
 ms.localizationpriority: medium
 ---
 
-# Manage submission options
+# Manage submission options for MSIX apps
 
 The **Submission options** page of the app submission process is where you can provide more information to help us test your product properly. This is an optional step, but is recommended for many submissions. You can also optionally set publishing hold options if you want to delay the publishing process.
 

hub/apps/publish/publish-your-app/msix/product-declarations.md

@@ -6,7 +6,7 @@ ms.topic: article
 ms.localizationpriority: medium
 ---
 
-# Product declarations
+# Product declarations for MSIX apps
 
 The **Product declarations** section of the [Properties](./enter-app-properties.md) page of the [submission process](./create-app-submission.md) helps make sure your app is displayed appropriately and offered to the right set of customers, and helps them understand how they can use your app.