docs: add information about invoice access

- Add new FAQ explaining how to access invoices
- Clarify in both Cody and Enterprise Starter docs that invoices are not emailed monthly
- Ensure consistent information across documentation

Author: enriquegh

docs/cody/usage-and-pricing.mdx

@@ -87,7 +87,7 @@ We don't offer refunds, but if you have any queries regarding the Cody Pro plan,
 
 ### How do I access previous invoices?
 
-You can access your invoices via the [Cody Dashboard](https://sourcegraph.com/cody/manage) and clicking "Manage Subscription".
+You can access your invoices via the [Cody Dashboard](https://sourcegraph.com/cody/manage) and clicking "Manage Subscription". Note that invoices are not emailed every month.
 
 ## Enterprise Starter
 

docs/pricing/faqs.mdx

@@ -105,6 +105,10 @@ On the **Workspace settings > General settings** page, you can delete your works
 
 Your subscription renewals are scheduled to happen on the same day of the month. On shorter months (e.g., day 31 on April, which only has 30 days), the last day of the month will be the subscription renewal day instead.
 
+## How do I access my invoices?
+
+You can access your invoices via the **Workspace settings > Billing** page by clicking the **View invoices** button, which takes you to the Stripe Customer Portal. Note that invoices are not emailed every month.
+
 ## How do I pay my invoice if my subscription is past due?
 
 After updating or resolving your payment method issue that occurred during the automatic subscription renewal, you may do one of the following to pay the invoice for your past-due subscription:

docs/pricing/plans/enterprise-starter.mdx

@@ -21,7 +21,7 @@ Workspaces on the Enterprise Starter plan are billed monthly based on the number
 
 If you fail to make the payment after the grace period, your workspace will be deleted, and you will not be able to recover your data.
 
-Please also see [Billing FAQs](billing-faqs.mdx) for more FAQs, including how to downgrade Enterprise Starter.
+Please also see [FAQs](faqs.mdx) for more FAQs, including how to downgrade Enterprise Starter.
 
 ## Features supported