add short titles to frontmatter (#20131)

content/developers/github-marketplace/creating-apps-for-github-marketplace/index.md

@@ -11,5 +11,6 @@ children:
   - /customer-experience-best-practices-for-apps
   - /viewing-metrics-for-your-listing
   - /viewing-transactions-for-your-listing
+shortTitle: Create Marketplace apps
 ---
 

content/developers/github-marketplace/creating-apps-for-github-marketplace/requirements-for-listing-an-app.md

@@ -13,6 +13,7 @@ versions:
   fpt: '*'
 topics:
   - Marketplace
+shortTitle: Listing requirements
 ---
 <!--UI-LINK: Displayed as a link on the https://github.com/marketplace/new page.-->
 

content/developers/github-marketplace/creating-apps-for-github-marketplace/viewing-metrics-for-your-listing.md

@@ -11,6 +11,7 @@ versions:
   fpt: '*'
 topics:
   - Marketplace
+shortTitle: View listing metrics
 ---
 You can view metrics for the past day (24 hours), week, month, or for the entire duration of time that your {% data variables.product.prodname_github_app %} has been listed.
 

content/developers/github-marketplace/creating-apps-for-github-marketplace/viewing-transactions-for-your-listing.md

@@ -8,6 +8,7 @@ versions:
   fpt: '*'
 topics:
   - Marketplace
+shortTitle: View listing transactions
 ---
 {% note %}