add short titles to frontmatter (#20131)

content/billing/managing-billing-for-git-large-file-storage/about-billing-for-git-large-file-storage.md

@@ -11,6 +11,7 @@ type: overview
 topics:
   - LFS
   - Upgrades
+shortTitle: About Git LFS billing
 ---
 ## About billing for {% data variables.large_files.product_name_long %}
 

content/billing/managing-billing-for-git-large-file-storage/downgrading-git-large-file-storage.md

@@ -15,6 +15,7 @@ topics:
   - LFS
   - Organizations
   - User account
+shortTitle: Downgrade Git LFS storage
 ---
 When you downgrade your number of data packs, your change takes effect on your next billing date. For more information, see "[About billing for {% data variables.large_files.product_name_long %}](/articles/about-billing-for-git-large-file-storage)."
 

content/billing/managing-billing-for-git-large-file-storage/upgrading-git-large-file-storage.md

@@ -15,6 +15,7 @@ topics:
   - Organizations
   - Upgrades
   - User account
+shortTitle: Upgrade Git LFS storage
 ---
 ## Purchasing additional storage and bandwidth for a personal account
 

content/billing/managing-billing-for-git-large-file-storage/viewing-your-git-large-file-storage-usage.md

@@ -14,6 +14,7 @@ topics:
   - LFS
   - Organizations
   - User account
+shortTitle: View Git LFS usage
 ---
 {% data reusables.large_files.owner_quota_only %} {% data reusables.large_files.does_not_carry %}